feat: implement MCP provider registry and service

- Add provider registry to manage LLM providers (Claude, Codex, Cursor, Gemini).
- Create provider routes for MCP server operations (list, upsert, delete, run).
- Implement MCP service for handling server operations and validations.
- Introduce abstract provider class and MCP provider base for shared functionality.
- Add tests for MCP server operations across different providers and scopes.
- Define shared interfaces and types for MCP functionality.
- Implement utility functions for handling JSON config files and API responses.

package.json

@@ -128,6 +128,8 @@
     "@commitlint/config-conventional": "^20.4.3",
     "@eslint/js": "^9.39.3",
     "@release-it/conventional-changelog": "^10.0.5",
+    "@types/cross-spawn": "^6.0.6",
+    "@types/express": "^5.0.6",
     "@types/node": "^22.19.7",
     "@types/react": "^18.2.43",
     "@types/react-dom": "^18.2.17",