feat(mcp): use project config as SSOT and sync enabled servers to ~/.claude.json

- Add McpConfig to MultiAppConfig and persist MCP servers in ~/.cc-switch/config.json
- Add Tauri commands: get_mcp_config, upsert_mcp_server_in_config, delete_mcp_server_in_config, set_mcp_enabled, sync_enabled_mcp_to_claude, import_mcp_from_claude
- Only write enabled MCPs to ~/.claude.json (mcpServers) and strip UI-only fields (enabled/source)
- Frontend: update API wrappers and MCP panel to read/write via config.json; seed presets on first open; import from ~/.claude.json
- Fix warnings (remove unused mut, dead code)
- Verified with cargo check and pnpm typecheck

src/vite-env.d.ts

@@ -1,6 +1,6 @@
 /// <reference types="vite/client" />
 
-import { Provider, Settings, CustomEndpoint, McpStatus } from "./types";
+import { Provider, Settings, CustomEndpoint, McpStatus, McpConfigResponse } from "./types";
 import { AppType } from "./lib/tauri-api";
 import type { UnlistenFn } from "@tauri-apps/api/event";
 
@@ -70,6 +70,16 @@ declare global {
       ) => Promise<boolean>;
       deleteClaudeMcpServer: (id: string) => Promise<boolean>;
       validateMcpCommand: (cmd: string) => Promise<boolean>;
+      // 新：config.json 为 SSOT 的 MCP API
+      getMcpConfig: () => Promise<McpConfigResponse>;
+      upsertMcpServerInConfig: (
+        id: string,
+        spec: Record<string, any>,
+      ) => Promise<boolean>;
+      deleteMcpServerInConfig: (id: string) => Promise<boolean>;
+      setMcpEnabled: (id: string, enabled: boolean) => Promise<boolean>;
+      syncEnabledMcpToClaude: () => Promise<boolean>;
+      importMcpFromClaude: () => Promise<number>;
       testApiEndpoints: (
         urls: string[],
         options?: { timeoutSecs?: number },