fix(mcp): migrate import functions to unified v3.7.0 structure

- Rewrite import_from_claude/codex/gemini to write directly to mcp.servers
- Implement skip-on-error strategy for fault tolerance (single invalid item no longer aborts entire batch)
- Smart merge logic: existing servers only enable corresponding app, preserve other configs
- Remove deprecated markers from service layer
- Export McpApps type for test usage
- Update mcp_commands tests to use unified structure

Fixes runtime import issue where data was written to legacy structure (mcp.claude/codex.servers)
but unified panel reads from new structure (mcp.servers), causing "imported but invisible" bug.

src-tauri/src/services/mcp.rs

@@ -231,11 +231,7 @@ impl McpService {
         Ok(())
     }
 
-    /// [已废弃] 从 Claude 导入 MCP（兼容旧 API）
-    #[deprecated(
-        since = "3.7.0",
-        note = "Import will be handled differently in unified structure"
-    )]
+    /// 从 Claude 导入 MCP（v3.7.0 已更新为统一结构）
     pub fn import_from_claude(state: &AppState) -> Result<usize, AppError> {
         let mut cfg = state.config.write()?;
         let count = mcp::import_from_claude(&mut cfg)?;
@@ -244,11 +240,7 @@ impl McpService {
         Ok(count)
     }
 
-    /// [已废弃] 从 Codex 导入 MCP（兼容旧 API）
-    #[deprecated(
-        since = "3.7.0",
-        note = "Import will be handled differently in unified structure"
-    )]
+    /// 从 Codex 导入 MCP（v3.7.0 已更新为统一结构）
     pub fn import_from_codex(state: &AppState) -> Result<usize, AppError> {
         let mut cfg = state.config.write()?;
         let count = mcp::import_from_codex(&mut cfg)?;
@@ -257,11 +249,7 @@ impl McpService {
         Ok(count)
     }
 
-    /// [已废弃] 从 Gemini 导入 MCP（兼容旧 API）
-    #[deprecated(
-        since = "3.7.0",
-        note = "Import will be handled differently in unified structure"
-    )]
+    /// 从 Gemini 导入 MCP（v3.7.0 已更新为统一结构）
     pub fn import_from_gemini(state: &AppState) -> Result<usize, AppError> {
         let mut cfg = state.config.write()?;
         let count = mcp::import_from_gemini(&mut cfg)?;