feat: add skill update detection via SHA-256 content hashing

- Add content_hash and updated_at fields to skills table (DB migration v6→v7)
- Compute directory content hash on install/import/restore for version tracking
- Add check_updates command: downloads repos, compares hashes, returns update list
- Add update_skill command: backs up old files, re-downloads and replaces SSOT
- Backfill content_hash for existing skills on first update check
- Add "Check Updates" button and per-skill update badge/button in UnifiedSkillsPanel
- Add i18n keys for zh/en/ja

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

@@ -22,7 +22,8 @@ impl Database {
         let mut stmt = conn
             .prepare(
                 "SELECT id, name, description, directory, repo_owner, repo_name, repo_branch,
-                        readme_url, enabled_claude, enabled_codex, enabled_gemini, enabled_opencode, installed_at
+                        readme_url, enabled_claude, enabled_codex, enabled_gemini, enabled_opencode,
+                        installed_at, content_hash, updated_at
                  FROM skills ORDER BY name ASC",
             )
             .map_err(|e| AppError::Database(e.to_string()))?;
@@ -45,6 +46,8 @@ impl Database {
                         opencode: row.get(11)?,
                     },
                     installed_at: row.get(12)?,
+                    content_hash: row.get(13)?,
+                    updated_at: row.get::<_, i64>(14).unwrap_or(0),
                 })
             })
             .map_err(|e| AppError::Database(e.to_string()))?;
@@ -63,7 +66,8 @@ impl Database {
         let mut stmt = conn
             .prepare(
                 "SELECT id, name, description, directory, repo_owner, repo_name, repo_branch,
-                        readme_url, enabled_claude, enabled_codex, enabled_gemini, enabled_opencode, installed_at
+                        readme_url, enabled_claude, enabled_codex, enabled_gemini, enabled_opencode,
+                        installed_at, content_hash, updated_at
                  FROM skills WHERE id = ?1",
             )
             .map_err(|e| AppError::Database(e.to_string()))?;
@@ -85,6 +89,8 @@ impl Database {
                     opencode: row.get(11)?,
                 },
                 installed_at: row.get(12)?,
+                content_hash: row.get(13)?,
+                updated_at: row.get::<_, i64>(14).unwrap_or(0),
             })
         });
 
@@ -101,8 +107,9 @@ impl Database {
         conn.execute(
             "INSERT OR REPLACE INTO skills
              (id, name, description, directory, repo_owner, repo_name, repo_branch,
-              readme_url, enabled_claude, enabled_codex, enabled_gemini, enabled_opencode, installed_at)
-             VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12, ?13)",
+              readme_url, enabled_claude, enabled_codex, enabled_gemini, enabled_opencode,
+              installed_at, content_hash, updated_at)
+             VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12, ?13, ?14, ?15)",
             params![
                 skill.id,
                 skill.name,
@@ -117,6 +124,8 @@ impl Database {
                 skill.apps.gemini,
                 skill.apps.opencode,
                 skill.installed_at,
+                skill.content_hash,
+                skill.updated_at,
             ],
         )
         .map_err(|e| AppError::Database(e.to_string()))?;
@@ -152,6 +161,23 @@ impl Database {
         Ok(affected > 0)
     }
 
+    /// 更新 Skill 的内容哈希和更新时间
+    pub fn update_skill_hash(
+        &self,
+        id: &str,
+        content_hash: &str,
+        updated_at: i64,
+    ) -> Result<bool, AppError> {
+        let conn = lock_conn!(self.conn);
+        let affected = conn
+            .execute(
+                "UPDATE skills SET content_hash = ?1, updated_at = ?2 WHERE id = ?3",
+                params![content_hash, updated_at, id],
+            )
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        Ok(affected > 0)
+    }
+
     // ========== SkillRepo CRUD（保持原有） ==========
 
     /// 获取所有 Skill 仓库

src-tauri/src/database/mod.rs

@@ -44,7 +44,7 @@ use std::sync::Mutex;
 
 /// 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 = 6;
+pub(crate) const SCHEMA_VERSION: i32 = 7;
 
 /// 安全地序列化 JSON，避免 unwrap panic
 pub(crate) fn to_json_string<T: Serialize>(value: &T) -> Result<String, AppError> {

src-tauri/src/database/schema.rs

@@ -93,7 +93,9 @@ impl Database {
             enabled_codex BOOLEAN NOT NULL DEFAULT 0,
             enabled_gemini BOOLEAN NOT NULL DEFAULT 0,
             enabled_opencode BOOLEAN NOT NULL DEFAULT 0,
-            installed_at INTEGER NOT NULL DEFAULT 0
+            installed_at INTEGER NOT NULL DEFAULT 0,
+            content_hash TEXT,
+            updated_at INTEGER NOT NULL DEFAULT 0
         )",
             [],
         )
@@ -393,6 +395,11 @@ impl Database {
                         Self::migrate_v5_to_v6(conn)?;
                         Self::set_user_version(conn, 6)?;
                     }
+                    6 => {
+                        log::info!("迁移数据库从 v6 到 v7（Skills 更新检测支持）");
+                        Self::migrate_v6_to_v7(conn)?;
+                        Self::set_user_version(conn, 7)?;
+                    }
                     _ => {
                         return Err(AppError::Database(format!(
                             "未知的数据库版本 {version}，无法迁移到 {SCHEMA_VERSION}"
@@ -1045,6 +1052,14 @@ impl Database {
         Ok(())
     }
 
+    /// v6 -> v7: Skills 更新检测支持（content_hash + updated_at）
+    fn migrate_v6_to_v7(conn: &Connection) -> Result<(), AppError> {
+        Self::add_column_if_missing(conn, "skills", "content_hash", "TEXT")?;
+        Self::add_column_if_missing(conn, "skills", "updated_at", "INTEGER NOT NULL DEFAULT 0")?;
+        log::info!("v6 -> v7 迁移完成：已添加 content_hash 和 updated_at 列");
+        Ok(())
+    }
+
     /// 插入默认模型定价数据
     /// 格式: (model_id, display_name, input, output, cache_read, cache_creation)
     /// 注意: model_id 使用短横线格式（如 claude-haiku-4-5），与 API 返回的模型名称标准化后一致