feat(opencode): Phase 1 - Backend data structure expansion for OpenCode support

Add OpenCode as the 4th supported application with additive provider management:

- Add OpenCode variant to AppType enum with all related match statements
- Add enabled_opencode field to McpApps and SkillApps structures
- Add opencode field to McpRoot and PromptRoot
- Add database schema migration v3→v4 with enabled_opencode columns
- Add settings.rs support for opencode_config_dir and current_provider_opencode
- Create opencode_config.rs module for config file I/O operations
- Update all services (proxy, mcp, skill, provider, stream_check) for OpenCode
- Add OpenCode support to deeplink provider and MCP parsing
- Update commands/config.rs for OpenCode config status and paths

Key design decisions:
- OpenCode uses additive mode (no is_current needed, no proxy support)
- Config path: ~/.config/opencode/opencode.json
- MCP format: stdio→local, sse/http→remote conversion planned
- Stream check returns error (not yet implemented for OpenCode)

src-tauri/src/opencode_config.rs

@@ -0,0 +1,154 @@
+//! OpenCode 配置文件读写模块
+//!
+//! 处理 `~/.config/opencode/opencode.json` 配置文件的读写操作。
+//! OpenCode 使用累加式供应商管理，所有供应商配置共存于同一配置文件中。
+
+use crate::error::AppError;
+use crate::settings::get_opencode_override_dir;
+use std::path::PathBuf;
+
+/// 获取 OpenCode 配置目录
+///
+/// 默认路径: `~/.config/opencode/`
+/// 可通过 settings.opencode_config_dir 覆盖
+pub fn get_opencode_dir() -> PathBuf {
+    if let Some(override_dir) = get_opencode_override_dir() {
+        return override_dir;
+    }
+
+    #[cfg(target_os = "windows")]
+    {
+        // Windows: %APPDATA%\opencode
+        dirs::data_dir()
+            .map(|d| d.join("opencode"))
+            .unwrap_or_else(|| PathBuf::from(".config").join("opencode"))
+    }
+
+    #[cfg(not(target_os = "windows"))]
+    {
+        // Unix: ~/.config/opencode
+        dirs::home_dir()
+            .map(|h| h.join(".config").join("opencode"))
+            .unwrap_or_else(|| PathBuf::from(".config").join("opencode"))
+    }
+}
+
+/// 获取 OpenCode 配置文件路径
+///
+/// 返回 `~/.config/opencode/opencode.json`
+pub fn get_opencode_config_path() -> PathBuf {
+    get_opencode_dir().join("opencode.json")
+}
+
+/// 读取 OpenCode 配置文件
+///
+/// 返回完整的配置 JSON 对象
+pub fn read_opencode_config() -> Result<serde_json::Value, AppError> {
+    let path = get_opencode_config_path();
+
+    if !path.exists() {
+        // Return empty config with schema
+        return Ok(serde_json::json!({
+            "$schema": "https://opencode.ai/config.json"
+        }));
+    }
+
+    let content = std::fs::read_to_string(&path).map_err(|e| AppError::io(&path, e))?;
+    serde_json::from_str(&content).map_err(|e| AppError::json(&path, e))
+}
+
+/// 写入 OpenCode 配置文件（原子写入）
+///
+/// 使用临时文件 + 重命名确保原子性
+pub fn write_opencode_config(config: &serde_json::Value) -> Result<(), AppError> {
+    let path = get_opencode_config_path();
+
+    // Ensure directory exists
+    if let Some(parent) = path.parent() {
+        std::fs::create_dir_all(parent).map_err(|e| AppError::io(parent, e))?;
+    }
+
+    // Write to temporary file first
+    let temp_path = path.with_extension("json.tmp");
+    let content = serde_json::to_string_pretty(config)
+        .map_err(|e| AppError::JsonSerialize { source: e })?;
+
+    std::fs::write(&temp_path, &content).map_err(|e| AppError::io(&temp_path, e))?;
+
+    // Atomic rename
+    std::fs::rename(&temp_path, &path).map_err(|e| AppError::io(&path, e))?;
+
+    Ok(())
+}
+
+/// 获取所有供应商配置
+pub fn get_providers() -> Result<serde_json::Map<String, serde_json::Value>, AppError> {
+    let config = read_opencode_config()?;
+    Ok(config
+        .get("provider")
+        .and_then(|v| v.as_object())
+        .cloned()
+        .unwrap_or_default())
+}
+
+/// 设置供应商配置
+pub fn set_provider(id: &str, config: serde_json::Value) -> Result<(), AppError> {
+    let mut full_config = read_opencode_config()?;
+
+    if full_config.get("provider").is_none() {
+        full_config["provider"] = serde_json::json!({});
+    }
+
+    if let Some(providers) = full_config.get_mut("provider").and_then(|v| v.as_object_mut()) {
+        providers.insert(id.to_string(), config);
+    }
+
+    write_opencode_config(&full_config)
+}
+
+/// 删除供应商配置
+pub fn remove_provider(id: &str) -> Result<(), AppError> {
+    let mut config = read_opencode_config()?;
+
+    if let Some(providers) = config.get_mut("provider").and_then(|v| v.as_object_mut()) {
+        providers.remove(id);
+    }
+
+    write_opencode_config(&config)
+}
+
+/// 获取所有 MCP 服务器配置
+pub fn get_mcp_servers() -> Result<serde_json::Map<String, serde_json::Value>, AppError> {
+    let config = read_opencode_config()?;
+    Ok(config
+        .get("mcp")
+        .and_then(|v| v.as_object())
+        .cloned()
+        .unwrap_or_default())
+}
+
+/// 设置 MCP 服务器配置
+pub fn set_mcp_server(id: &str, config: serde_json::Value) -> Result<(), AppError> {
+    let mut full_config = read_opencode_config()?;
+
+    if full_config.get("mcp").is_none() {
+        full_config["mcp"] = serde_json::json!({});
+    }
+
+    if let Some(mcp) = full_config.get_mut("mcp").and_then(|v| v.as_object_mut()) {
+        mcp.insert(id.to_string(), config);
+    }
+
+    write_opencode_config(&full_config)
+}
+
+/// 删除 MCP 服务器配置
+pub fn remove_mcp_server(id: &str) -> Result<(), AppError> {
+    let mut config = read_opencode_config()?;
+
+    if let Some(mcp) = config.get_mut("mcp").and_then(|v| v.as_object_mut()) {
+        mcp.remove(id);
+    }
+
+    write_opencode_config(&config)
+}