refactor(database): split monolithic database.rs into modular structure

Split the 1788-line database.rs into a well-organized module directory:

- mod.rs (142 lines): Database struct and initialization
- schema.rs (341 lines): Table creation and schema migrations
- backup.rs (324 lines): SQL import/export and snapshot backup
- migration.rs (240 lines): JSON to SQLite data migration
- tests.rs (280 lines): Unit tests
- dao/providers.rs (254 lines): Provider CRUD operations
- dao/mcp.rs (97 lines): MCP server CRUD operations
- dao/prompts.rs (88 lines): Prompt CRUD operations
- dao/skills.rs (124 lines): Skills CRUD operations
- dao/settings.rs (65 lines): Settings key-value storage

Benefits:
- Max file size reduced from 1788 to 341 lines
- Clear separation of concerns (schema, backup, migration, DAOs)
- Easier to navigate and maintain
- All 107 tests passing with zero API changes

src-tauri/src/database/backup.rs

@@ -0,0 +1,324 @@
+//! 数据库备份和恢复
+//!
+//! 提供 SQL 导出/导入和二进制快照备份功能。
+
+use super::{lock_conn, Database, DB_BACKUP_RETAIN};
+use crate::config::get_app_config_dir;
+use crate::error::AppError;
+use chrono::Utc;
+use rusqlite::backup::Backup;
+use rusqlite::types::ValueRef;
+use rusqlite::Connection;
+use std::fs;
+use std::path::{Path, PathBuf};
+use tempfile::NamedTempFile;
+
+impl Database {
+    /// 导出为 SQLite 兼容的 SQL 文本
+    pub fn export_sql(&self, target_path: &Path) -> Result<(), AppError> {
+        let snapshot = self.snapshot_to_memory()?;
+        let dump = Self::dump_sql(&snapshot)?;
+
+        if let Some(parent) = target_path.parent() {
+            fs::create_dir_all(parent).map_err(|e| AppError::io(parent, e))?;
+        }
+
+        crate::config::atomic_write(target_path, dump.as_bytes())
+    }
+
+    /// 从 SQL 文件导入，返回生成的备份 ID（若无备份则为空字符串）
+    pub fn import_sql(&self, source_path: &Path) -> Result<String, AppError> {
+        if !source_path.exists() {
+            return Err(AppError::InvalidInput(format!(
+                "SQL 文件不存在: {}",
+                source_path.display()
+            )));
+        }
+
+        let sql_raw = fs::read_to_string(source_path).map_err(|e| AppError::io(source_path, e))?;
+        let sql_content = Self::sanitize_import_sql(&sql_raw);
+
+        // 导入前备份现有数据库
+        let backup_path = self.backup_database_file()?;
+
+        // 在临时数据库执行导入，确保失败不会污染主库
+        let temp_file = NamedTempFile::new().map_err(|e| AppError::IoContext {
+            context: "创建临时数据库文件失败".to_string(),
+            source: e,
+        })?;
+        let temp_path = temp_file.path().to_path_buf();
+        let temp_conn =
+            Connection::open(&temp_path).map_err(|e| AppError::Database(e.to_string()))?;
+
+        temp_conn
+            .execute_batch(&sql_content)
+            .map_err(|e| AppError::Database(format!("执行 SQL 导入失败: {e}")))?;
+
+        // 补齐缺失表/索引并进行基础校验
+        Self::create_tables_on_conn(&temp_conn)?;
+        Self::apply_schema_migrations_on_conn(&temp_conn)?;
+        Self::validate_basic_state(&temp_conn)?;
+
+        // 使用 Backup 将临时库原子写回主库
+        {
+            let mut main_conn = lock_conn!(self.conn);
+            let backup = Backup::new(&temp_conn, &mut main_conn)
+                .map_err(|e| AppError::Database(e.to_string()))?;
+            backup
+                .step(-1)
+                .map_err(|e| AppError::Database(e.to_string()))?;
+        }
+
+        let backup_id = backup_path
+            .and_then(|p| p.file_stem().map(|s| s.to_string_lossy().to_string()))
+            .unwrap_or_default();
+
+        Ok(backup_id)
+    }
+
+    /// 创建内存快照以避免长时间持有数据库锁
+    pub(crate) fn snapshot_to_memory(&self) -> Result<Connection, AppError> {
+        let conn = lock_conn!(self.conn);
+        let mut snapshot =
+            Connection::open_in_memory().map_err(|e| AppError::Database(e.to_string()))?;
+
+        {
+            let backup =
+                Backup::new(&conn, &mut snapshot).map_err(|e| AppError::Database(e.to_string()))?;
+            backup
+                .step(-1)
+                .map_err(|e| AppError::Database(e.to_string()))?;
+        }
+
+        Ok(snapshot)
+    }
+
+    /// 移除 SQLite 保留对象相关语句（如 sqlite_sequence），避免导入报错
+    fn sanitize_import_sql(sql: &str) -> String {
+        let mut cleaned = String::new();
+        let lower_keyword = "sqlite_sequence";
+
+        for stmt in sql.split(';') {
+            let trimmed = stmt.trim();
+            if trimmed.is_empty() {
+                continue;
+            }
+
+            if trimmed.to_ascii_lowercase().contains(lower_keyword) {
+                continue;
+            }
+
+            cleaned.push_str(trimmed);
+            cleaned.push_str(";\n");
+        }
+
+        cleaned
+    }
+
+    /// 生成一致性快照备份，返回备份文件路径（不存在主库时返回 None）
+    fn backup_database_file(&self) -> Result<Option<PathBuf>, AppError> {
+        let db_path = get_app_config_dir().join("cc-switch.db");
+        if !db_path.exists() {
+            return Ok(None);
+        }
+
+        let backup_dir = db_path
+            .parent()
+            .ok_or_else(|| AppError::Config("无效的数据库路径".to_string()))?
+            .join("backups");
+
+        fs::create_dir_all(&backup_dir).map_err(|e| AppError::io(&backup_dir, e))?;
+
+        let backup_id = format!("db_backup_{}", Utc::now().format("%Y%m%d_%H%M%S"));
+        let backup_path = backup_dir.join(format!("{backup_id}.db"));
+
+        {
+            let conn = lock_conn!(self.conn);
+            let mut dest_conn =
+                Connection::open(&backup_path).map_err(|e| AppError::Database(e.to_string()))?;
+            let backup = Backup::new(&conn, &mut dest_conn)
+                .map_err(|e| AppError::Database(e.to_string()))?;
+            backup
+                .step(-1)
+                .map_err(|e| AppError::Database(e.to_string()))?;
+        }
+
+        Self::cleanup_db_backups(&backup_dir)?;
+        Ok(Some(backup_path))
+    }
+
+    /// 清理旧的数据库备份，保留最新的 N 个
+    fn cleanup_db_backups(dir: &Path) -> Result<(), AppError> {
+        let entries = match fs::read_dir(dir) {
+            Ok(iter) => iter
+                .filter_map(|entry| entry.ok())
+                .filter(|entry| {
+                    entry
+                        .path()
+                        .extension()
+                        .map(|ext| ext == "db")
+                        .unwrap_or(false)
+                })
+                .collect::<Vec<_>>(),
+            Err(_) => return Ok(()),
+        };
+
+        if entries.len() <= DB_BACKUP_RETAIN {
+            return Ok(());
+        }
+
+        let remove_count = entries.len().saturating_sub(DB_BACKUP_RETAIN);
+        let mut sorted = entries;
+        sorted.sort_by_key(|entry| entry.metadata().and_then(|m| m.modified()).ok());
+
+        for entry in sorted.into_iter().take(remove_count) {
+            if let Err(err) = fs::remove_file(entry.path()) {
+                log::warn!("删除旧数据库备份失败 {}: {}", entry.path().display(), err);
+            }
+        }
+        Ok(())
+    }
+
+    /// 基础状态校验
+    fn validate_basic_state(conn: &Connection) -> Result<(), AppError> {
+        let provider_count: i64 = conn
+            .query_row("SELECT COUNT(*) FROM providers", [], |row| row.get(0))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        let mcp_count: i64 = conn
+            .query_row("SELECT COUNT(*) FROM mcp_servers", [], |row| row.get(0))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        if provider_count == 0 && mcp_count == 0 {
+            return Err(AppError::Config(
+                "导入的 SQL 未包含有效的供应商或 MCP 数据".to_string(),
+            ));
+        }
+        Ok(())
+    }
+
+    /// 导出数据库为 SQL 文本
+    fn dump_sql(conn: &Connection) -> Result<String, AppError> {
+        let mut output = String::new();
+        let timestamp = Utc::now().format("%Y-%m-%d %H:%M:%S").to_string();
+        let user_version: i64 = conn
+            .query_row("PRAGMA user_version;", [], |row| row.get(0))
+            .unwrap_or(0);
+
+        output.push_str(&format!(
+            "-- CC Switch SQLite 导出\n-- 生成时间: {timestamp}\n-- user_version: {user_version}\n"
+        ));
+        output.push_str("PRAGMA foreign_keys=OFF;\n");
+        output.push_str(&format!("PRAGMA user_version={user_version};\n"));
+        output.push_str("BEGIN TRANSACTION;\n");
+
+        // 导出 schema
+        let mut stmt = conn
+            .prepare(
+                "SELECT type, name, tbl_name, sql
+                 FROM sqlite_master
+                 WHERE sql NOT NULL AND type IN ('table','index','trigger','view')
+                 ORDER BY type='table' DESC, name",
+            )
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut tables = Vec::new();
+        let mut rows = stmt
+            .query([])
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        while let Some(row) = rows.next().map_err(|e| AppError::Database(e.to_string()))? {
+            let obj_type: String = row.get(0).map_err(|e| AppError::Database(e.to_string()))?;
+            let name: String = row.get(1).map_err(|e| AppError::Database(e.to_string()))?;
+            let sql: String = row.get(3).map_err(|e| AppError::Database(e.to_string()))?;
+
+            // 跳过 SQLite 内部对象（如 sqlite_sequence）
+            if name.starts_with("sqlite_") {
+                continue;
+            }
+
+            output.push_str(&sql);
+            output.push_str(";\n");
+
+            if obj_type == "table" && !name.starts_with("sqlite_") {
+                tables.push(name);
+            }
+        }
+
+        // 导出数据
+        for table in tables {
+            let columns = Self::get_table_columns(conn, &table)?;
+            if columns.is_empty() {
+                continue;
+            }
+
+            let mut stmt = conn
+                .prepare(&format!("SELECT * FROM \"{table}\""))
+                .map_err(|e| AppError::Database(e.to_string()))?;
+            let mut rows = stmt
+                .query([])
+                .map_err(|e| AppError::Database(e.to_string()))?;
+
+            while let Some(row) = rows.next().map_err(|e| AppError::Database(e.to_string()))? {
+                let mut values = Vec::with_capacity(columns.len());
+                for idx in 0..columns.len() {
+                    let value = row
+                        .get_ref(idx)
+                        .map_err(|e| AppError::Database(e.to_string()))?;
+                    values.push(Self::format_sql_value(value)?);
+                }
+
+                let cols = columns
+                    .iter()
+                    .map(|c| format!("\"{c}\""))
+                    .collect::<Vec<_>>()
+                    .join(", ");
+                output.push_str(&format!(
+                    "INSERT INTO \"{table}\" ({cols}) VALUES ({});\n",
+                    values.join(", ")
+                ));
+            }
+        }
+
+        output.push_str("COMMIT;\nPRAGMA foreign_keys=ON;\n");
+        Ok(output)
+    }
+
+    /// 获取表的列名列表
+    fn get_table_columns(conn: &Connection, table: &str) -> Result<Vec<String>, AppError> {
+        let mut stmt = conn
+            .prepare(&format!("PRAGMA table_info(\"{table}\")"))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        let iter = stmt
+            .query_map([], |row| row.get::<_, String>(1))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut columns = Vec::new();
+        for col in iter {
+            columns.push(col.map_err(|e| AppError::Database(e.to_string()))?);
+        }
+        Ok(columns)
+    }
+
+    /// 格式化 SQL 值
+    fn format_sql_value(value: ValueRef<'_>) -> Result<String, AppError> {
+        match value {
+            ValueRef::Null => Ok("NULL".to_string()),
+            ValueRef::Integer(i) => Ok(i.to_string()),
+            ValueRef::Real(f) => Ok(f.to_string()),
+            ValueRef::Text(t) => {
+                let text = std::str::from_utf8(t)
+                    .map_err(|e| AppError::Database(format!("文本字段不是有效的 UTF-8: {e}")))?;
+                let escaped = text.replace('\'', "''");
+                Ok(format!("'{escaped}'"))
+            }
+            ValueRef::Blob(bytes) => {
+                let mut s = String::from("X'");
+                for b in bytes {
+                    use std::fmt::Write;
+                    let _ = write!(&mut s, "{b:02X}");
+                }
+                s.push('\'');
+                Ok(s)
+            }
+        }
+    }
+}

src-tauri/src/database/dao/mcp.rs

@@ -0,0 +1,97 @@
+//! MCP 服务器数据访问对象
+//!
+//! 提供 MCP 服务器的 CRUD 操作。
+
+use crate::app_config::{McpApps, McpServer};
+use crate::database::{lock_conn, Database};
+use crate::error::AppError;
+use indexmap::IndexMap;
+use rusqlite::params;
+
+impl Database {
+    /// 获取所有 MCP 服务器
+    pub fn get_all_mcp_servers(&self) -> Result<IndexMap<String, McpServer>, AppError> {
+        let conn = lock_conn!(self.conn);
+        let mut stmt = conn.prepare(
+            "SELECT id, name, server_config, description, homepage, docs, tags, enabled_claude, enabled_codex, enabled_gemini
+             FROM mcp_servers
+             ORDER BY name ASC, id ASC"
+        ).map_err(|e| AppError::Database(e.to_string()))?;
+
+        let server_iter = stmt
+            .query_map([], |row| {
+                let id: String = row.get(0)?;
+                let name: String = row.get(1)?;
+                let server_config_str: String = row.get(2)?;
+                let description: Option<String> = row.get(3)?;
+                let homepage: Option<String> = row.get(4)?;
+                let docs: Option<String> = row.get(5)?;
+                let tags_str: String = row.get(6)?;
+                let enabled_claude: bool = row.get(7)?;
+                let enabled_codex: bool = row.get(8)?;
+                let enabled_gemini: bool = row.get(9)?;
+
+                let server = serde_json::from_str(&server_config_str).unwrap_or_default();
+                let tags = serde_json::from_str(&tags_str).unwrap_or_default();
+
+                Ok((
+                    id.clone(),
+                    McpServer {
+                        id,
+                        name,
+                        server,
+                        apps: McpApps {
+                            claude: enabled_claude,
+                            codex: enabled_codex,
+                            gemini: enabled_gemini,
+                        },
+                        description,
+                        homepage,
+                        docs,
+                        tags,
+                    },
+                ))
+            })
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut servers = IndexMap::new();
+        for server_res in server_iter {
+            let (id, server) = server_res.map_err(|e| AppError::Database(e.to_string()))?;
+            servers.insert(id, server);
+        }
+        Ok(servers)
+    }
+
+    /// 保存 MCP 服务器
+    pub fn save_mcp_server(&self, server: &McpServer) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        conn.execute(
+            "INSERT OR REPLACE INTO mcp_servers (
+                id, name, server_config, description, homepage, docs, tags,
+                enabled_claude, enabled_codex, enabled_gemini
+            ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10)",
+            params![
+                server.id,
+                server.name,
+                serde_json::to_string(&server.server).unwrap(),
+                server.description,
+                server.homepage,
+                server.docs,
+                serde_json::to_string(&server.tags).unwrap(),
+                server.apps.claude,
+                server.apps.codex,
+                server.apps.gemini,
+            ],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+
+    /// 删除 MCP 服务器
+    pub fn delete_mcp_server(&self, id: &str) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        conn.execute("DELETE FROM mcp_servers WHERE id = ?1", params![id])
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+}

src-tauri/src/database/dao/mod.rs

@@ -0,0 +1,11 @@
+//! 数据访问对象 (DAO) 模块
+//!
+//! 提供各类数据的 CRUD 操作。
+
+mod mcp;
+mod prompts;
+mod providers;
+mod settings;
+mod skills;
+
+// 所有 DAO 方法都通过 Database impl 提供，无需单独导出

src-tauri/src/database/dao/prompts.rs

@@ -0,0 +1,88 @@
+//! 提示词数据访问对象
+//!
+//! 提供提示词（Prompt）的 CRUD 操作。
+
+use crate::database::{lock_conn, Database};
+use crate::error::AppError;
+use crate::prompt::Prompt;
+use indexmap::IndexMap;
+use rusqlite::params;
+
+impl Database {
+    /// 获取指定应用类型的所有提示词
+    pub fn get_prompts(&self, app_type: &str) -> Result<IndexMap<String, Prompt>, AppError> {
+        let conn = lock_conn!(self.conn);
+        let mut stmt = conn
+            .prepare(
+                "SELECT id, name, content, description, enabled, created_at, updated_at
+             FROM prompts WHERE app_type = ?1
+             ORDER BY created_at ASC, id ASC",
+            )
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let prompt_iter = stmt
+            .query_map(params![app_type], |row| {
+                let id: String = row.get(0)?;
+                let name: String = row.get(1)?;
+                let content: String = row.get(2)?;
+                let description: Option<String> = row.get(3)?;
+                let enabled: bool = row.get(4)?;
+                let created_at: Option<i64> = row.get(5)?;
+                let updated_at: Option<i64> = row.get(6)?;
+
+                Ok((
+                    id.clone(),
+                    Prompt {
+                        id,
+                        name,
+                        content,
+                        description,
+                        enabled,
+                        created_at,
+                        updated_at,
+                    },
+                ))
+            })
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut prompts = IndexMap::new();
+        for prompt_res in prompt_iter {
+            let (id, prompt) = prompt_res.map_err(|e| AppError::Database(e.to_string()))?;
+            prompts.insert(id, prompt);
+        }
+        Ok(prompts)
+    }
+
+    /// 保存提示词
+    pub fn save_prompt(&self, app_type: &str, prompt: &Prompt) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        conn.execute(
+            "INSERT OR REPLACE INTO prompts (
+                id, app_type, name, content, description, enabled, created_at, updated_at
+            ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)",
+            params![
+                prompt.id,
+                app_type,
+                prompt.name,
+                prompt.content,
+                prompt.description,
+                prompt.enabled,
+                prompt.created_at,
+                prompt.updated_at,
+            ],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+
+    /// 删除提示词
+    pub fn delete_prompt(&self, app_type: &str, id: &str) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        conn.execute(
+            "DELETE FROM prompts WHERE id = ?1 AND app_type = ?2",
+            params![id, app_type],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+}

src-tauri/src/database/dao/providers.rs

@@ -0,0 +1,254 @@
+//! 供应商数据访问对象
+//!
+//! 提供供应商（Provider）的 CRUD 操作。
+
+use crate::database::{lock_conn, Database};
+use crate::error::AppError;
+use crate::provider::{Provider, ProviderMeta};
+use indexmap::IndexMap;
+use rusqlite::params;
+use std::collections::HashMap;
+
+impl Database {
+    /// 获取指定应用类型的所有供应商
+    pub fn get_all_providers(
+        &self,
+        app_type: &str,
+    ) -> Result<IndexMap<String, Provider>, AppError> {
+        let conn = lock_conn!(self.conn);
+        let mut stmt = conn.prepare(
+            "SELECT id, name, settings_config, website_url, category, created_at, sort_index, notes, icon, icon_color, meta
+             FROM providers WHERE app_type = ?1
+             ORDER BY COALESCE(sort_index, 999999), created_at ASC, id ASC"
+        ).map_err(|e| AppError::Database(e.to_string()))?;
+
+        let provider_iter = stmt
+            .query_map(params![app_type], |row| {
+                let id: String = row.get(0)?;
+                let name: String = row.get(1)?;
+                let settings_config_str: String = row.get(2)?;
+                let website_url: Option<String> = row.get(3)?;
+                let category: Option<String> = row.get(4)?;
+                let created_at: Option<i64> = row.get(5)?;
+                let sort_index: Option<usize> = row.get(6)?;
+                let notes: Option<String> = row.get(7)?;
+                let icon: Option<String> = row.get(8)?;
+                let icon_color: Option<String> = row.get(9)?;
+                let meta_str: String = row.get(10)?;
+
+                let settings_config =
+                    serde_json::from_str(&settings_config_str).unwrap_or(serde_json::Value::Null);
+                let meta: ProviderMeta = serde_json::from_str(&meta_str).unwrap_or_default();
+
+                Ok((
+                    id,
+                    Provider {
+                        id: "".to_string(), // Placeholder, set below
+                        name,
+                        settings_config,
+                        website_url,
+                        category,
+                        created_at,
+                        sort_index,
+                        notes,
+                        meta: Some(meta),
+                        icon,
+                        icon_color,
+                    },
+                ))
+            })
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut providers = IndexMap::new();
+        for provider_res in provider_iter {
+            let (id, mut provider) = provider_res.map_err(|e| AppError::Database(e.to_string()))?;
+            provider.id = id.clone();
+
+            // 加载 endpoints
+            let mut stmt_endpoints = conn.prepare(
+                "SELECT url, added_at FROM provider_endpoints WHERE provider_id = ?1 AND app_type = ?2 ORDER BY added_at ASC, url ASC"
+            ).map_err(|e| AppError::Database(e.to_string()))?;
+
+            let endpoints_iter = stmt_endpoints
+                .query_map(params![id, app_type], |row| {
+                    let url: String = row.get(0)?;
+                    let added_at: Option<i64> = row.get(1)?;
+                    Ok((
+                        url,
+                        crate::settings::CustomEndpoint {
+                            url: "".to_string(),
+                            added_at: added_at.unwrap_or(0),
+                            last_used: None,
+                        },
+                    ))
+                })
+                .map_err(|e| AppError::Database(e.to_string()))?;
+
+            let mut custom_endpoints = HashMap::new();
+            for ep_res in endpoints_iter {
+                let (url, mut ep) = ep_res.map_err(|e| AppError::Database(e.to_string()))?;
+                ep.url = url.clone();
+                custom_endpoints.insert(url, ep);
+            }
+
+            if let Some(meta) = &mut provider.meta {
+                meta.custom_endpoints = custom_endpoints;
+            }
+
+            providers.insert(id, provider);
+        }
+
+        Ok(providers)
+    }
+
+    /// 获取当前激活的供应商 ID
+    pub fn get_current_provider(&self, app_type: &str) -> Result<Option<String>, AppError> {
+        let conn = lock_conn!(self.conn);
+        let mut stmt = conn
+            .prepare("SELECT id FROM providers WHERE app_type = ?1 AND is_current = 1 LIMIT 1")
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut rows = stmt
+            .query(params![app_type])
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        if let Some(row) = rows.next().map_err(|e| AppError::Database(e.to_string()))? {
+            Ok(Some(
+                row.get(0).map_err(|e| AppError::Database(e.to_string()))?,
+            ))
+        } else {
+            Ok(None)
+        }
+    }
+
+    /// 保存供应商（新增或更新）
+    pub fn save_provider(&self, app_type: &str, provider: &Provider) -> Result<(), AppError> {
+        let mut conn = lock_conn!(self.conn);
+        let tx = conn
+            .transaction()
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 处理 meta 和 endpoints
+        let mut meta_clone = provider.meta.clone().unwrap_or_default();
+        let endpoints = std::mem::take(&mut meta_clone.custom_endpoints);
+
+        // 检查是否存在以保留 is_current
+        let is_current: bool = tx
+            .query_row(
+                "SELECT is_current FROM providers WHERE id = ?1 AND app_type = ?2",
+                params![provider.id, app_type],
+                |row| row.get(0),
+            )
+            .unwrap_or(false);
+
+        tx.execute(
+            "INSERT OR REPLACE INTO providers (
+                id, app_type, name, settings_config, website_url, category,
+                created_at, sort_index, notes, icon, icon_color, meta, is_current
+            ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12, ?13)",
+            params![
+                provider.id,
+                app_type,
+                provider.name,
+                serde_json::to_string(&provider.settings_config).unwrap(),
+                provider.website_url,
+                provider.category,
+                provider.created_at,
+                provider.sort_index,
+                provider.notes,
+                provider.icon,
+                provider.icon_color,
+                serde_json::to_string(&meta_clone).unwrap(),
+                is_current,
+            ],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 同步 endpoints：删除全部后重新插入
+        tx.execute(
+            "DELETE FROM provider_endpoints WHERE provider_id = ?1 AND app_type = ?2",
+            params![provider.id, app_type],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        for (url, endpoint) in endpoints {
+            tx.execute(
+                "INSERT INTO provider_endpoints (provider_id, app_type, url, added_at)
+                 VALUES (?1, ?2, ?3, ?4)",
+                params![provider.id, app_type, url, endpoint.added_at],
+            )
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        }
+
+        tx.commit().map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+
+    /// 删除供应商
+    pub fn delete_provider(&self, app_type: &str, id: &str) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        conn.execute(
+            "DELETE FROM providers WHERE id = ?1 AND app_type = ?2",
+            params![id, app_type],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+
+    /// 设置当前供应商
+    pub fn set_current_provider(&self, app_type: &str, id: &str) -> Result<(), AppError> {
+        let mut conn = lock_conn!(self.conn);
+        let tx = conn
+            .transaction()
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 重置所有为 0
+        tx.execute(
+            "UPDATE providers SET is_current = 0 WHERE app_type = ?1",
+            params![app_type],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 设置新的当前供应商
+        tx.execute(
+            "UPDATE providers SET is_current = 1 WHERE id = ?1 AND app_type = ?2",
+            params![id, app_type],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        tx.commit().map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+
+    /// 添加自定义端点
+    pub fn add_custom_endpoint(
+        &self,
+        app_type: &str,
+        provider_id: &str,
+        url: &str,
+    ) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        let added_at = chrono::Utc::now().timestamp_millis();
+        conn.execute(
+            "INSERT INTO provider_endpoints (provider_id, app_type, url, added_at) VALUES (?1, ?2, ?3, ?4)",
+            params![provider_id, app_type, url, added_at],
+        ).map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+
+    /// 移除自定义端点
+    pub fn remove_custom_endpoint(
+        &self,
+        app_type: &str,
+        provider_id: &str,
+        url: &str,
+    ) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        conn.execute(
+            "DELETE FROM provider_endpoints WHERE provider_id = ?1 AND app_type = ?2 AND url = ?3",
+            params![provider_id, app_type, url],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+}

src-tauri/src/database/dao/settings.rs

@@ -0,0 +1,65 @@
+//! 通用设置数据访问对象
+//!
+//! 提供键值对形式的通用设置存储。
+
+use crate::database::{lock_conn, Database};
+use crate::error::AppError;
+use rusqlite::params;
+
+impl Database {
+    /// 获取设置值
+    pub fn get_setting(&self, key: &str) -> Result<Option<String>, AppError> {
+        let conn = lock_conn!(self.conn);
+        let mut stmt = conn
+            .prepare("SELECT value FROM settings WHERE key = ?1")
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut rows = stmt
+            .query(params![key])
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        if let Some(row) = rows.next().map_err(|e| AppError::Database(e.to_string()))? {
+            Ok(Some(
+                row.get(0).map_err(|e| AppError::Database(e.to_string()))?,
+            ))
+        } else {
+            Ok(None)
+        }
+    }
+
+    /// 设置值
+    pub fn set_setting(&self, key: &str, value: &str) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        conn.execute(
+            "INSERT OR REPLACE INTO settings (key, value) VALUES (?1, ?2)",
+            params![key, value],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+
+    // --- Config Snippets 辅助方法 ---
+
+    /// 获取通用配置片段
+    pub fn get_config_snippet(&self, app_type: &str) -> Result<Option<String>, AppError> {
+        self.get_setting(&format!("common_config_{app_type}"))
+    }
+
+    /// 设置通用配置片段
+    pub fn set_config_snippet(
+        &self,
+        app_type: &str,
+        snippet: Option<String>,
+    ) -> Result<(), AppError> {
+        let key = format!("common_config_{app_type}");
+        if let Some(value) = snippet {
+            self.set_setting(&key, &value)
+        } else {
+            // 如果为 None 则删除
+            let conn = lock_conn!(self.conn);
+            conn.execute("DELETE FROM settings WHERE key = ?1", params![key])
+                .map_err(|e| AppError::Database(e.to_string()))?;
+            Ok(())
+        }
+    }
+}

src-tauri/src/database/dao/skills.rs

@@ -0,0 +1,124 @@
+//! Skills 数据访问对象
+//!
+//! 提供 Skills 和 Skill Repos 的 CRUD 操作。
+
+use crate::database::{lock_conn, Database};
+use crate::error::AppError;
+use crate::services::skill::{SkillRepo, SkillState};
+use indexmap::IndexMap;
+use rusqlite::params;
+
+impl Database {
+    /// 获取所有 Skills 状态
+    pub fn get_skills(&self) -> Result<IndexMap<String, SkillState>, AppError> {
+        let conn = lock_conn!(self.conn);
+        let mut stmt = conn
+            .prepare("SELECT key, installed, installed_at FROM skills ORDER BY key ASC")
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let skill_iter = stmt
+            .query_map([], |row| {
+                let key: String = row.get(0)?;
+                let installed: bool = row.get(1)?;
+                let installed_at_ts: i64 = row.get(2)?;
+
+                let installed_at =
+                    chrono::DateTime::from_timestamp(installed_at_ts, 0).unwrap_or_default();
+
+                Ok((
+                    key,
+                    SkillState {
+                        installed,
+                        installed_at,
+                    },
+                ))
+            })
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut skills = IndexMap::new();
+        for skill_res in skill_iter {
+            let (key, skill) = skill_res.map_err(|e| AppError::Database(e.to_string()))?;
+            skills.insert(key, skill);
+        }
+        Ok(skills)
+    }
+
+    /// 更新 Skill 状态
+    pub fn update_skill_state(&self, key: &str, state: &SkillState) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        conn.execute(
+            "INSERT OR REPLACE INTO skills (key, installed, installed_at) VALUES (?1, ?2, ?3)",
+            params![key, state.installed, state.installed_at.timestamp()],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+
+    /// 获取所有 Skill 仓库
+    pub fn get_skill_repos(&self) -> Result<Vec<SkillRepo>, AppError> {
+        let conn = lock_conn!(self.conn);
+        let mut stmt = conn
+            .prepare("SELECT owner, name, branch, enabled, skills_path FROM skill_repos ORDER BY owner ASC, name ASC")
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let repo_iter = stmt
+            .query_map([], |row| {
+                Ok(SkillRepo {
+                    owner: row.get(0)?,
+                    name: row.get(1)?,
+                    branch: row.get(2)?,
+                    enabled: row.get(3)?,
+                    skills_path: row.get(4)?,
+                })
+            })
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut repos = Vec::new();
+        for repo_res in repo_iter {
+            repos.push(repo_res.map_err(|e| AppError::Database(e.to_string()))?);
+        }
+        Ok(repos)
+    }
+
+    /// 保存 Skill 仓库
+    pub fn save_skill_repo(&self, repo: &SkillRepo) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        conn.execute(
+            "INSERT OR REPLACE INTO skill_repos (owner, name, branch, enabled, skills_path) VALUES (?1, ?2, ?3, ?4, ?5)",
+            params![repo.owner, repo.name, repo.branch, repo.enabled, repo.skills_path],
+        ).map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+
+    /// 删除 Skill 仓库
+    pub fn delete_skill_repo(&self, owner: &str, name: &str) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        conn.execute(
+            "DELETE FROM skill_repos WHERE owner = ?1 AND name = ?2",
+            params![owner, name],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(())
+    }
+
+    /// 初始化默认的 Skill 仓库（首次启动时调用）
+    pub fn init_default_skill_repos(&self) -> Result<usize, AppError> {
+        // 检查是否已有仓库
+        let existing = self.get_skill_repos()?;
+        if !existing.is_empty() {
+            return Ok(0);
+        }
+
+        // 获取默认仓库列表
+        let default_store = crate::services::skill::SkillStore::default();
+        let mut count = 0;
+
+        for repo in &default_store.repos {
+            self.save_skill_repo(repo)?;
+            count += 1;
+        }
+
+        log::info!("初始化默认 Skill 仓库完成，共 {count} 个");
+        Ok(count)
+    }
+}

src-tauri/src/database/migration.rs

@@ -0,0 +1,240 @@
+//! JSON → SQLite 数据迁移
+//!
+//! 将旧版 config.json (MultiAppConfig) 数据迁移到 SQLite 数据库。
+
+use super::{lock_conn, to_json_string, Database};
+use crate::app_config::MultiAppConfig;
+use crate::error::AppError;
+use rusqlite::{params, Connection};
+
+impl Database {
+    /// 从 MultiAppConfig 迁移数据到数据库
+    pub fn migrate_from_json(&self, config: &MultiAppConfig) -> Result<(), AppError> {
+        let mut conn = lock_conn!(self.conn);
+        let tx = conn
+            .transaction()
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        Self::migrate_from_json_tx(&tx, config)?;
+
+        tx.commit()
+            .map_err(|e| AppError::Database(format!("Commit migration failed: {e}")))?;
+        Ok(())
+    }
+
+    /// 运行迁移的 dry-run 模式（在内存数据库中验证，不写入磁盘）
+    ///
+    /// 用于部署前验证迁移逻辑是否正确。
+    pub fn migrate_from_json_dry_run(config: &MultiAppConfig) -> Result<(), AppError> {
+        let mut conn =
+            Connection::open_in_memory().map_err(|e| AppError::Database(e.to_string()))?;
+        Self::create_tables_on_conn(&conn)?;
+        Self::apply_schema_migrations_on_conn(&conn)?;
+
+        let tx = conn
+            .transaction()
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        Self::migrate_from_json_tx(&tx, config)?;
+
+        // 显式 drop transaction 而不提交（内存数据库会被丢弃）
+        drop(tx);
+        Ok(())
+    }
+
+    /// 在事务中执行迁移
+    fn migrate_from_json_tx(
+        tx: &rusqlite::Transaction<'_>,
+        config: &MultiAppConfig,
+    ) -> Result<(), AppError> {
+        // 1. 迁移 Providers
+        Self::migrate_providers(tx, config)?;
+
+        // 2. 迁移 MCP Servers
+        Self::migrate_mcp_servers(tx, config)?;
+
+        // 3. 迁移 Prompts
+        Self::migrate_prompts(tx, config)?;
+
+        // 4. 迁移 Skills
+        Self::migrate_skills(tx, config)?;
+
+        // 5. 迁移 Common Config
+        Self::migrate_common_config(tx, config)?;
+
+        Ok(())
+    }
+
+    /// 迁移供应商数据
+    fn migrate_providers(
+        tx: &rusqlite::Transaction<'_>,
+        config: &MultiAppConfig,
+    ) -> Result<(), AppError> {
+        for (app_key, manager) in &config.apps {
+            let app_type = app_key;
+            let current_id = &manager.current;
+
+            for (id, provider) in &manager.providers {
+                let is_current = if id == current_id { 1 } else { 0 };
+
+                // 处理 meta 和 endpoints
+                let mut meta_clone = provider.meta.clone().unwrap_or_default();
+                let endpoints = std::mem::take(&mut meta_clone.custom_endpoints);
+
+                tx.execute(
+                    "INSERT OR REPLACE INTO providers (
+                        id, app_type, name, settings_config, website_url, category,
+                        created_at, sort_index, notes, icon, icon_color, meta, is_current
+                    ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12, ?13)",
+                    params![
+                        id,
+                        app_type,
+                        provider.name,
+                        to_json_string(&provider.settings_config)?,
+                        provider.website_url,
+                        provider.category,
+                        provider.created_at,
+                        provider.sort_index,
+                        provider.notes,
+                        provider.icon,
+                        provider.icon_color,
+                        to_json_string(&meta_clone)?,
+                        is_current,
+                    ],
+                )
+                .map_err(|e| AppError::Database(format!("Migrate provider failed: {e}")))?;
+
+                // 迁移 Endpoints
+                for (url, endpoint) in endpoints {
+                    tx.execute(
+                        "INSERT INTO provider_endpoints (provider_id, app_type, url, added_at)
+                         VALUES (?1, ?2, ?3, ?4)",
+                        params![id, app_type, url, endpoint.added_at],
+                    )
+                    .map_err(|e| AppError::Database(format!("Migrate endpoint failed: {e}")))?;
+                }
+            }
+        }
+        Ok(())
+    }
+
+    /// 迁移 MCP 服务器数据
+    fn migrate_mcp_servers(
+        tx: &rusqlite::Transaction<'_>,
+        config: &MultiAppConfig,
+    ) -> Result<(), AppError> {
+        if let Some(servers) = &config.mcp.servers {
+            for (id, server) in servers {
+                tx.execute(
+                    "INSERT OR REPLACE INTO mcp_servers (
+                        id, name, server_config, description, homepage, docs, tags,
+                        enabled_claude, enabled_codex, enabled_gemini
+                    ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10)",
+                    params![
+                        id,
+                        server.name,
+                        to_json_string(&server.server)?,
+                        server.description,
+                        server.homepage,
+                        server.docs,
+                        to_json_string(&server.tags)?,
+                        server.apps.claude,
+                        server.apps.codex,
+                        server.apps.gemini,
+                    ],
+                )
+                .map_err(|e| AppError::Database(format!("Migrate mcp server failed: {e}")))?;
+            }
+        }
+        Ok(())
+    }
+
+    /// 迁移提示词数据
+    fn migrate_prompts(
+        tx: &rusqlite::Transaction<'_>,
+        config: &MultiAppConfig,
+    ) -> Result<(), AppError> {
+        let migrate_app_prompts =
+            |prompts_map: &std::collections::HashMap<String, crate::prompt::Prompt>,
+             app_type: &str|
+             -> Result<(), AppError> {
+                for (id, prompt) in prompts_map {
+                    tx.execute(
+                        "INSERT OR REPLACE INTO prompts (
+                            id, app_type, name, content, description, enabled, created_at, updated_at
+                        ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)",
+                        params![
+                            id,
+                            app_type,
+                            prompt.name,
+                            prompt.content,
+                            prompt.description,
+                            prompt.enabled,
+                            prompt.created_at,
+                            prompt.updated_at,
+                        ],
+                    )
+                    .map_err(|e| AppError::Database(format!("Migrate prompt failed: {e}")))?;
+                }
+                Ok(())
+            };
+
+        migrate_app_prompts(&config.prompts.claude.prompts, "claude")?;
+        migrate_app_prompts(&config.prompts.codex.prompts, "codex")?;
+        migrate_app_prompts(&config.prompts.gemini.prompts, "gemini")?;
+
+        Ok(())
+    }
+
+    /// 迁移 Skills 数据
+    fn migrate_skills(
+        tx: &rusqlite::Transaction<'_>,
+        config: &MultiAppConfig,
+    ) -> Result<(), AppError> {
+        for (key, state) in &config.skills.skills {
+            tx.execute(
+                "INSERT OR REPLACE INTO skills (key, installed, installed_at) VALUES (?1, ?2, ?3)",
+                params![key, state.installed, state.installed_at.timestamp()],
+            )
+            .map_err(|e| AppError::Database(format!("Migrate skill failed: {e}")))?;
+        }
+
+        for repo in &config.skills.repos {
+            tx.execute(
+                "INSERT OR REPLACE INTO skill_repos (owner, name, branch, enabled, skills_path) VALUES (?1, ?2, ?3, ?4, ?5)",
+                params![repo.owner, repo.name, repo.branch, repo.enabled, repo.skills_path],
+            ).map_err(|e| AppError::Database(format!("Migrate skill repo failed: {e}")))?;
+        }
+
+        Ok(())
+    }
+
+    /// 迁移通用配置片段
+    fn migrate_common_config(
+        tx: &rusqlite::Transaction<'_>,
+        config: &MultiAppConfig,
+    ) -> Result<(), AppError> {
+        if let Some(snippet) = &config.common_config_snippets.claude {
+            tx.execute(
+                "INSERT OR REPLACE INTO settings (key, value) VALUES (?1, ?2)",
+                params!["common_config_claude", snippet],
+            )
+            .map_err(|e| AppError::Database(format!("Migrate settings failed: {e}")))?;
+        }
+        if let Some(snippet) = &config.common_config_snippets.codex {
+            tx.execute(
+                "INSERT OR REPLACE INTO settings (key, value) VALUES (?1, ?2)",
+                params!["common_config_codex", snippet],
+            )
+            .map_err(|e| AppError::Database(format!("Migrate settings failed: {e}")))?;
+        }
+        if let Some(snippet) = &config.common_config_snippets.gemini {
+            tx.execute(
+                "INSERT OR REPLACE INTO settings (key, value) VALUES (?1, ?2)",
+                params!["common_config_gemini", snippet],
+            )
+            .map_err(|e| AppError::Database(format!("Migrate settings failed: {e}")))?;
+        }
+
+        Ok(())
+    }
+}

src-tauri/src/database/mod.rs

@@ -0,0 +1,142 @@
+//! 数据库模块 - SQLite 数据持久化
+//!
+//! 此模块提供应用的核心数据存储功能，包括：
+//! - 供应商配置管理
+//! - MCP 服务器配置
+//! - 提示词管理
+//! - Skills 管理
+//! - 通用设置存储
+//!
+//! ## 架构设计
+//!
+//! ```text
+//! database/
+//! ├── mod.rs        - Database 结构体 + 初始化
+//! ├── schema.rs     - 表结构定义 + Schema 迁移
+//! ├── backup.rs     - SQL 导入导出 + 快照备份
+//! ├── migration.rs  - JSON → SQLite 数据迁移
+//! └── dao/          - 数据访问对象
+//!     ├── providers.rs
+//!     ├── mcp.rs
+//!     ├── prompts.rs
+//!     ├── skills.rs
+//!     └── settings.rs
+//! ```
+
+mod backup;
+mod dao;
+mod migration;
+mod schema;
+
+#[cfg(test)]
+mod tests;
+
+use crate::config::get_app_config_dir;
+use crate::error::AppError;
+use rusqlite::Connection;
+use serde::Serialize;
+use std::sync::Mutex;
+
+// DAO 方法通过 impl Database 提供，无需额外导出
+
+/// 数据库备份保留数量
+const DB_BACKUP_RETAIN: usize = 10;
+
+/// 当前 Schema 版本号
+/// 每次修改表结构时递增，并在 schema.rs 中添加相应的迁移逻辑
+pub(crate) const SCHEMA_VERSION: i32 = 1;
+
+/// 安全地序列化 JSON，避免 unwrap panic
+pub(crate) fn to_json_string<T: Serialize>(value: &T) -> Result<String, AppError> {
+    serde_json::to_string(value)
+        .map_err(|e| AppError::Config(format!("JSON serialization failed: {e}")))
+}
+
+/// 安全地获取 Mutex 锁，避免 unwrap panic
+macro_rules! lock_conn {
+    ($mutex:expr) => {
+        $mutex
+            .lock()
+            .map_err(|e| AppError::Database(format!("Mutex lock failed: {}", e)))?
+    };
+}
+
+// 导出宏供子模块使用
+pub(crate) use lock_conn;
+
+/// 数据库连接封装
+///
+/// 使用 Mutex 包装 Connection 以支持在多线程环境（如 Tauri State）中共享。
+/// rusqlite::Connection 本身不是 Sync 的，因此需要这层包装。
+pub struct Database {
+    pub(crate) conn: Mutex<Connection>,
+}
+
+impl Database {
+    /// 初始化数据库连接并创建表
+    ///
+    /// 数据库文件位于 `~/.cc-switch/cc-switch.db`
+    pub fn init() -> Result<Self, AppError> {
+        let db_path = get_app_config_dir().join("cc-switch.db");
+
+        // 确保父目录存在
+        if let Some(parent) = db_path.parent() {
+            std::fs::create_dir_all(parent).map_err(|e| AppError::io(parent, e))?;
+        }
+
+        let conn = Connection::open(&db_path).map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 启用外键约束
+        conn.execute("PRAGMA foreign_keys = ON;", [])
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let db = Self {
+            conn: Mutex::new(conn),
+        };
+        db.create_tables()?;
+        db.apply_schema_migrations()?;
+
+        Ok(db)
+    }
+
+    /// 创建内存数据库（用于测试）
+    pub fn memory() -> Result<Self, AppError> {
+        let conn = Connection::open_in_memory().map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 启用外键约束
+        conn.execute("PRAGMA foreign_keys = ON;", [])
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let db = Self {
+            conn: Mutex::new(conn),
+        };
+        db.create_tables()?;
+
+        Ok(db)
+    }
+
+    /// 检查数据库是否为空（需要首次导入）
+    ///
+    /// 通过检查是否有任何 MCP 服务器、提示词、Skills 仓库或供应商来判断
+    pub fn is_empty_for_first_import(&self) -> Result<bool, AppError> {
+        let conn = lock_conn!(self.conn);
+
+        let mcp_count: i64 = conn
+            .query_row("SELECT COUNT(*) FROM mcp_servers", [], |row| row.get(0))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let prompt_count: i64 = conn
+            .query_row("SELECT COUNT(*) FROM prompts", [], |row| row.get(0))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let skill_repo_count: i64 = conn
+            .query_row("SELECT COUNT(*) FROM skill_repos", [], |row| row.get(0))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let provider_count: i64 = conn
+            .query_row("SELECT COUNT(*) FROM providers", [], |row| row.get(0))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        Ok(mcp_count == 0 && prompt_count == 0 && skill_repo_count == 0 && provider_count == 0)
+    }
+}

src-tauri/src/database/schema.rs

@@ -0,0 +1,341 @@
+//! Schema 定义和迁移
+//!
+//! 负责数据库表结构的创建和版本迁移。
+
+use super::{lock_conn, Database, SCHEMA_VERSION};
+use crate::error::AppError;
+use rusqlite::Connection;
+
+impl Database {
+    /// 创建所有数据库表
+    pub(crate) fn create_tables(&self) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        Self::create_tables_on_conn(&conn)
+    }
+
+    /// 在指定连接上创建表（供迁移和测试使用）
+    pub(crate) fn create_tables_on_conn(conn: &Connection) -> Result<(), AppError> {
+        // 1. Providers 表
+        conn.execute(
+            "CREATE TABLE IF NOT EXISTS providers (
+                id TEXT NOT NULL,
+                app_type TEXT NOT NULL,
+                name TEXT NOT NULL,
+                settings_config TEXT NOT NULL,
+                website_url TEXT,
+                category TEXT,
+                created_at INTEGER,
+                sort_index INTEGER,
+                notes TEXT,
+                icon TEXT,
+                icon_color TEXT,
+                meta TEXT NOT NULL DEFAULT '{}',
+                is_current BOOLEAN NOT NULL DEFAULT 0,
+                PRIMARY KEY (id, app_type)
+            )",
+            [],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 2. Provider Endpoints 表
+        conn.execute(
+            "CREATE TABLE IF NOT EXISTS provider_endpoints (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                provider_id TEXT NOT NULL,
+                app_type TEXT NOT NULL,
+                url TEXT NOT NULL,
+                added_at INTEGER,
+                FOREIGN KEY (provider_id, app_type) REFERENCES providers(id, app_type) ON DELETE CASCADE
+            )",
+            [],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 3. MCP Servers 表
+        conn.execute(
+            "CREATE TABLE IF NOT EXISTS mcp_servers (
+                id TEXT PRIMARY KEY,
+                name TEXT NOT NULL,
+                server_config TEXT NOT NULL,
+                description TEXT,
+                homepage TEXT,
+                docs TEXT,
+                tags TEXT NOT NULL DEFAULT '[]',
+                enabled_claude BOOLEAN NOT NULL DEFAULT 0,
+                enabled_codex BOOLEAN NOT NULL DEFAULT 0,
+                enabled_gemini BOOLEAN NOT NULL DEFAULT 0
+            )",
+            [],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 4. Prompts 表
+        conn.execute(
+            "CREATE TABLE IF NOT EXISTS prompts (
+                id TEXT NOT NULL,
+                app_type TEXT NOT NULL,
+                name TEXT NOT NULL,
+                content TEXT NOT NULL,
+                description TEXT,
+                enabled BOOLEAN NOT NULL DEFAULT 1,
+                created_at INTEGER,
+                updated_at INTEGER,
+                PRIMARY KEY (id, app_type)
+            )",
+            [],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 5. Skills 表
+        conn.execute(
+            "CREATE TABLE IF NOT EXISTS skills (
+                key TEXT PRIMARY KEY,
+                installed BOOLEAN NOT NULL DEFAULT 0,
+                installed_at INTEGER NOT NULL DEFAULT 0
+            )",
+            [],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 6. Skill Repos 表
+        conn.execute(
+            "CREATE TABLE IF NOT EXISTS skill_repos (
+                owner TEXT NOT NULL,
+                name TEXT NOT NULL,
+                branch TEXT NOT NULL DEFAULT 'main',
+                enabled BOOLEAN NOT NULL DEFAULT 1,
+                skills_path TEXT,
+                PRIMARY KEY (owner, name)
+            )",
+            [],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 7. Settings 表 (通用配置)
+        conn.execute(
+            "CREATE TABLE IF NOT EXISTS settings (
+                key TEXT PRIMARY KEY,
+                value TEXT
+            )",
+            [],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        Ok(())
+    }
+
+    /// 应用 Schema 迁移
+    pub(crate) fn apply_schema_migrations(&self) -> Result<(), AppError> {
+        let conn = lock_conn!(self.conn);
+        Self::apply_schema_migrations_on_conn(&conn)
+    }
+
+    /// 在指定连接上应用 Schema 迁移
+    pub(crate) fn apply_schema_migrations_on_conn(conn: &Connection) -> Result<(), AppError> {
+        conn.execute("SAVEPOINT schema_migration;", [])
+            .map_err(|e| AppError::Database(format!("开启迁移 savepoint 失败: {e}")))?;
+
+        let mut version = Self::get_user_version(conn)?;
+
+        if version > SCHEMA_VERSION {
+            conn.execute("ROLLBACK TO schema_migration;", []).ok();
+            conn.execute("RELEASE schema_migration;", []).ok();
+            return Err(AppError::Database(format!(
+                "数据库版本过新（{version}），当前应用仅支持 {SCHEMA_VERSION}，请升级应用后再尝试。"
+            )));
+        }
+
+        let result = (|| {
+            while version < SCHEMA_VERSION {
+                match version {
+                    0 => {
+                        log::info!("检测到 user_version=0，迁移到 1（补齐缺失列并设置版本）");
+                        Self::migrate_v0_to_v1(conn)?;
+                        Self::set_user_version(conn, SCHEMA_VERSION)?;
+                    }
+                    _ => {
+                        return Err(AppError::Database(format!(
+                            "未知的数据库版本 {version}，无法迁移到 {SCHEMA_VERSION}"
+                        )));
+                    }
+                }
+                version = Self::get_user_version(conn)?;
+            }
+            Ok(())
+        })();
+
+        match result {
+            Ok(_) => {
+                conn.execute("RELEASE schema_migration;", [])
+                    .map_err(|e| AppError::Database(format!("提交迁移 savepoint 失败: {e}")))?;
+                Ok(())
+            }
+            Err(e) => {
+                conn.execute("ROLLBACK TO schema_migration;", []).ok();
+                conn.execute("RELEASE schema_migration;", []).ok();
+                Err(e)
+            }
+        }
+    }
+
+    /// v0 -> v1 迁移：补齐所有缺失列
+    fn migrate_v0_to_v1(conn: &Connection) -> Result<(), AppError> {
+        // providers 表
+        Self::add_column_if_missing(conn, "providers", "category", "TEXT")?;
+        Self::add_column_if_missing(conn, "providers", "created_at", "INTEGER")?;
+        Self::add_column_if_missing(conn, "providers", "sort_index", "INTEGER")?;
+        Self::add_column_if_missing(conn, "providers", "notes", "TEXT")?;
+        Self::add_column_if_missing(conn, "providers", "icon", "TEXT")?;
+        Self::add_column_if_missing(conn, "providers", "icon_color", "TEXT")?;
+        Self::add_column_if_missing(conn, "providers", "meta", "TEXT NOT NULL DEFAULT '{}'")?;
+        Self::add_column_if_missing(
+            conn,
+            "providers",
+            "is_current",
+            "BOOLEAN NOT NULL DEFAULT 0",
+        )?;
+
+        // provider_endpoints 表
+        Self::add_column_if_missing(conn, "provider_endpoints", "added_at", "INTEGER")?;
+
+        // mcp_servers 表
+        Self::add_column_if_missing(conn, "mcp_servers", "description", "TEXT")?;
+        Self::add_column_if_missing(conn, "mcp_servers", "homepage", "TEXT")?;
+        Self::add_column_if_missing(conn, "mcp_servers", "docs", "TEXT")?;
+        Self::add_column_if_missing(conn, "mcp_servers", "tags", "TEXT NOT NULL DEFAULT '[]'")?;
+        Self::add_column_if_missing(
+            conn,
+            "mcp_servers",
+            "enabled_codex",
+            "BOOLEAN NOT NULL DEFAULT 0",
+        )?;
+        Self::add_column_if_missing(
+            conn,
+            "mcp_servers",
+            "enabled_gemini",
+            "BOOLEAN NOT NULL DEFAULT 0",
+        )?;
+
+        // prompts 表
+        Self::add_column_if_missing(conn, "prompts", "description", "TEXT")?;
+        Self::add_column_if_missing(conn, "prompts", "enabled", "BOOLEAN NOT NULL DEFAULT 1")?;
+        Self::add_column_if_missing(conn, "prompts", "created_at", "INTEGER")?;
+        Self::add_column_if_missing(conn, "prompts", "updated_at", "INTEGER")?;
+
+        // skills 表
+        Self::add_column_if_missing(conn, "skills", "installed_at", "INTEGER NOT NULL DEFAULT 0")?;
+
+        // skill_repos 表
+        Self::add_column_if_missing(conn, "skill_repos", "branch", "TEXT NOT NULL DEFAULT 'main'")?;
+        Self::add_column_if_missing(
+            conn,
+            "skill_repos",
+            "enabled",
+            "BOOLEAN NOT NULL DEFAULT 1",
+        )?;
+        Self::add_column_if_missing(conn, "skill_repos", "skills_path", "TEXT")?;
+
+        Ok(())
+    }
+
+    // --- 辅助方法 ---
+
+    pub(crate) fn get_user_version(conn: &Connection) -> Result<i32, AppError> {
+        conn.query_row("PRAGMA user_version;", [], |row| row.get(0))
+            .map_err(|e| AppError::Database(format!("读取 user_version 失败: {e}")))
+    }
+
+    pub(crate) fn set_user_version(conn: &Connection, version: i32) -> Result<(), AppError> {
+        if version < 0 {
+            return Err(AppError::Database(
+                "user_version 不能为负数".to_string(),
+            ));
+        }
+        let sql = format!("PRAGMA user_version = {version};");
+        conn.execute(&sql, [])
+            .map_err(|e| AppError::Database(format!("写入 user_version 失败: {e}")))?;
+        Ok(())
+    }
+
+    fn validate_identifier(s: &str, kind: &str) -> Result<(), AppError> {
+        if s.is_empty() {
+            return Err(AppError::Database(format!("{kind} 不能为空")));
+        }
+        if !s
+            .chars()
+            .all(|c| c.is_ascii_alphanumeric() || c == '_')
+        {
+            return Err(AppError::Database(format!(
+                "非法{kind}: {s}，仅允许字母、数字和下划线"
+            )));
+        }
+        Ok(())
+    }
+
+    pub(crate) fn table_exists(conn: &Connection, table: &str) -> Result<bool, AppError> {
+        Self::validate_identifier(table, "表名")?;
+
+        let mut stmt = conn
+            .prepare("SELECT name FROM sqlite_master WHERE type='table'")
+            .map_err(|e| AppError::Database(format!("读取表名失败: {e}")))?;
+        let mut rows = stmt
+            .query([])
+            .map_err(|e| AppError::Database(format!("查询表名失败: {e}")))?;
+        while let Some(row) = rows.next().map_err(|e| AppError::Database(e.to_string()))? {
+            let name: String = row
+                .get(0)
+                .map_err(|e| AppError::Database(format!("解析表名失败: {e}")))?;
+            if name.eq_ignore_ascii_case(table) {
+                return Ok(true);
+            }
+        }
+        Ok(false)
+    }
+
+    pub(crate) fn has_column(conn: &Connection, table: &str, column: &str) -> Result<bool, AppError> {
+        Self::validate_identifier(table, "表名")?;
+        Self::validate_identifier(column, "列名")?;
+
+        let sql = format!("PRAGMA table_info(\"{table}\");");
+        let mut stmt = conn
+            .prepare(&sql)
+            .map_err(|e| AppError::Database(format!("读取表结构失败: {e}")))?;
+        let mut rows = stmt
+            .query([])
+            .map_err(|e| AppError::Database(format!("查询表结构失败: {e}")))?;
+        while let Some(row) = rows.next().map_err(|e| AppError::Database(e.to_string()))? {
+            let name: String = row
+                .get(1)
+                .map_err(|e| AppError::Database(format!("读取列名失败: {e}")))?;
+            if name.eq_ignore_ascii_case(column) {
+                return Ok(true);
+            }
+        }
+        Ok(false)
+    }
+
+    fn add_column_if_missing(
+        conn: &Connection,
+        table: &str,
+        column: &str,
+        definition: &str,
+    ) -> Result<bool, AppError> {
+        Self::validate_identifier(table, "表名")?;
+        Self::validate_identifier(column, "列名")?;
+
+        if !Self::table_exists(conn, table)? {
+            return Err(AppError::Database(format!(
+                "表 {table} 不存在，无法添加列 {column}"
+            )));
+        }
+        if Self::has_column(conn, table, column)? {
+            return Ok(false);
+        }
+
+        let sql = format!("ALTER TABLE \"{table}\" ADD COLUMN \"{column}\" {definition};");
+        conn.execute(&sql, [])
+            .map_err(|e| AppError::Database(format!("为表 {table} 添加列 {column} 失败: {e}")))?;
+        log::info!("已为表 {table} 添加缺失列 {column}");
+        Ok(true)
+    }
+}

src-tauri/src/database/tests.rs

@@ -0,0 +1,280 @@
+//! 数据库模块测试
+//!
+//! 包含 Schema 迁移和基本功能的测试。
+
+use super::*;
+use crate::app_config::MultiAppConfig;
+use crate::provider::{Provider, ProviderManager};
+use indexmap::IndexMap;
+use rusqlite::Connection;
+use serde_json::json;
+use std::collections::HashMap;
+
+const LEGACY_SCHEMA_SQL: &str = r#"
+    CREATE TABLE providers (
+        id TEXT NOT NULL,
+        app_type TEXT NOT NULL,
+        name TEXT NOT NULL,
+        settings_config TEXT NOT NULL,
+        PRIMARY KEY (id, app_type)
+    );
+    CREATE TABLE provider_endpoints (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        provider_id TEXT NOT NULL,
+        app_type TEXT NOT NULL,
+        url TEXT NOT NULL
+    );
+    CREATE TABLE mcp_servers (
+        id TEXT PRIMARY KEY,
+        name TEXT NOT NULL,
+        server_config TEXT NOT NULL
+    );
+    CREATE TABLE prompts (
+        id TEXT NOT NULL,
+        app_type TEXT NOT NULL,
+        name TEXT NOT NULL,
+        content TEXT NOT NULL,
+        PRIMARY KEY (id, app_type)
+    );
+    CREATE TABLE skills (
+        key TEXT PRIMARY KEY,
+        installed BOOLEAN NOT NULL DEFAULT 0
+    );
+    CREATE TABLE skill_repos (
+        owner TEXT NOT NULL,
+        name TEXT NOT NULL,
+        PRIMARY KEY (owner, name)
+    );
+    CREATE TABLE settings (
+        key TEXT PRIMARY KEY,
+        value TEXT
+    );
+"#;
+
+#[derive(Debug)]
+struct ColumnInfo {
+    name: String,
+    r#type: String,
+    notnull: i64,
+    default: Option<String>,
+}
+
+fn get_column_info(conn: &Connection, table: &str, column: &str) -> ColumnInfo {
+    let mut stmt = conn
+        .prepare(&format!("PRAGMA table_info(\"{table}\");"))
+        .expect("prepare pragma");
+    let mut rows = stmt.query([]).expect("query pragma");
+    while let Some(row) = rows.next().expect("read row") {
+        let name: String = row.get(1).expect("name");
+        if name.eq_ignore_ascii_case(column) {
+            return ColumnInfo {
+                name,
+                r#type: row.get::<_, String>(2).expect("type"),
+                notnull: row.get::<_, i64>(3).expect("notnull"),
+                default: row.get::<_, Option<String>>(4).ok().flatten(),
+            };
+        }
+    }
+    panic!("column {table}.{column} not found");
+}
+
+fn normalize_default(default: &Option<String>) -> Option<String> {
+    default
+        .as_ref()
+        .map(|s| s.trim_matches('\'').trim_matches('"').to_string())
+}
+
+#[test]
+fn migration_sets_user_version_when_missing() {
+    let conn = Connection::open_in_memory().expect("open memory db");
+
+    Database::create_tables_on_conn(&conn).expect("create tables");
+    assert_eq!(
+        Database::get_user_version(&conn).expect("read version before"),
+        0
+    );
+
+    Database::apply_schema_migrations_on_conn(&conn).expect("apply migration");
+
+    assert_eq!(
+        Database::get_user_version(&conn).expect("read version after"),
+        SCHEMA_VERSION
+    );
+}
+
+#[test]
+fn migration_rejects_future_version() {
+    let conn = Connection::open_in_memory().expect("open memory db");
+    Database::create_tables_on_conn(&conn).expect("create tables");
+    Database::set_user_version(&conn, SCHEMA_VERSION + 1).expect("set future version");
+
+    let err = Database::apply_schema_migrations_on_conn(&conn)
+        .expect_err("should reject higher version");
+    assert!(
+        err.to_string().contains("数据库版本过新"),
+        "unexpected error: {err}"
+    );
+}
+
+#[test]
+fn migration_adds_missing_columns_for_providers() {
+    let conn = Connection::open_in_memory().expect("open memory db");
+
+    // 创建旧版 providers 表，缺少新增列
+    conn.execute_batch(LEGACY_SCHEMA_SQL)
+        .expect("seed old schema");
+
+    Database::apply_schema_migrations_on_conn(&conn).expect("apply migrations");
+
+    // 验证关键新增列已补齐
+    for (table, column) in [
+        ("providers", "meta"),
+        ("providers", "is_current"),
+        ("provider_endpoints", "added_at"),
+        ("mcp_servers", "enabled_gemini"),
+        ("prompts", "updated_at"),
+        ("skills", "installed_at"),
+        ("skill_repos", "enabled"),
+    ] {
+        assert!(
+            Database::has_column(&conn, table, column).expect("check column"),
+            "{table}.{column} should exist after migration"
+        );
+    }
+
+    // 验证 meta 列约束保持一致
+    let meta = get_column_info(&conn, "providers", "meta");
+    assert_eq!(meta.notnull, 1, "meta should be NOT NULL");
+    assert_eq!(
+        normalize_default(&meta.default).as_deref(),
+        Some("{}"),
+        "meta default should be '{{}}'"
+    );
+
+    assert_eq!(
+        Database::get_user_version(&conn).expect("version after migration"),
+        SCHEMA_VERSION
+    );
+}
+
+#[test]
+fn migration_aligns_column_defaults_and_types() {
+    let conn = Connection::open_in_memory().expect("open memory db");
+    conn.execute_batch(LEGACY_SCHEMA_SQL)
+        .expect("seed old schema");
+
+    Database::apply_schema_migrations_on_conn(&conn).expect("apply migrations");
+
+    let is_current = get_column_info(&conn, "providers", "is_current");
+    assert_eq!(is_current.r#type, "BOOLEAN");
+    assert_eq!(is_current.notnull, 1);
+    assert_eq!(
+        normalize_default(&is_current.default).as_deref(),
+        Some("0")
+    );
+
+    let tags = get_column_info(&conn, "mcp_servers", "tags");
+    assert_eq!(tags.r#type, "TEXT");
+    assert_eq!(tags.notnull, 1);
+    assert_eq!(normalize_default(&tags.default).as_deref(), Some("[]"));
+
+    let enabled = get_column_info(&conn, "prompts", "enabled");
+    assert_eq!(enabled.r#type, "BOOLEAN");
+    assert_eq!(enabled.notnull, 1);
+    assert_eq!(
+        normalize_default(&enabled.default).as_deref(),
+        Some("1")
+    );
+
+    let installed_at = get_column_info(&conn, "skills", "installed_at");
+    assert_eq!(installed_at.r#type, "INTEGER");
+    assert_eq!(installed_at.notnull, 1);
+    assert_eq!(
+        normalize_default(&installed_at.default).as_deref(),
+        Some("0")
+    );
+
+    let branch = get_column_info(&conn, "skill_repos", "branch");
+    assert_eq!(branch.r#type, "TEXT");
+    assert_eq!(normalize_default(&branch.default).as_deref(), Some("main"));
+
+    let skill_repo_enabled = get_column_info(&conn, "skill_repos", "enabled");
+    assert_eq!(skill_repo_enabled.r#type, "BOOLEAN");
+    assert_eq!(skill_repo_enabled.notnull, 1);
+    assert_eq!(
+        normalize_default(&skill_repo_enabled.default).as_deref(),
+        Some("1")
+    );
+}
+
+#[test]
+fn dry_run_does_not_write_to_disk() {
+    // Create minimal valid config for migration
+    let mut apps = HashMap::new();
+    apps.insert("claude".to_string(), ProviderManager::default());
+
+    let config = MultiAppConfig {
+        version: 2,
+        apps,
+        mcp: Default::default(),
+        prompts: Default::default(),
+        skills: Default::default(),
+        common_config_snippets: Default::default(),
+        claude_common_config_snippet: None,
+    };
+
+    // Dry-run should succeed without any file I/O errors
+    let result = Database::migrate_from_json_dry_run(&config);
+    assert!(
+        result.is_ok(),
+        "Dry-run should succeed with valid config: {result:?}"
+    );
+}
+
+#[test]
+fn dry_run_validates_schema_compatibility() {
+    // Create config with actual provider data
+    let mut providers = IndexMap::new();
+    providers.insert(
+        "test-provider".to_string(),
+        Provider {
+            id: "test-provider".to_string(),
+            name: "Test Provider".to_string(),
+            settings_config: json!({
+                "anthropicApiKey": "sk-test-123",
+            }),
+            website_url: None,
+            category: None,
+            created_at: Some(1234567890),
+            sort_index: None,
+            notes: None,
+            meta: None,
+            icon: None,
+            icon_color: None,
+        },
+    );
+
+    let mut manager = ProviderManager::default();
+    manager.providers = providers;
+    manager.current = "test-provider".to_string();
+
+    let mut apps = HashMap::new();
+    apps.insert("claude".to_string(), manager);
+
+    let config = MultiAppConfig {
+        version: 2,
+        apps,
+        mcp: Default::default(),
+        prompts: Default::default(),
+        skills: Default::default(),
+        common_config_snippets: Default::default(),
+        claude_common_config_snippet: None,
+    };
+
+    // Dry-run should validate the full migration path
+    let result = Database::migrate_from_json_dry_run(&config);
+    assert!(
+        result.is_ok(),
+        "Dry-run should succeed with provider data: {result:?}"
+    );
+}