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.

server/modules/providers/list/codex/codex.provider.ts

@@ -0,0 +1,10 @@
+import { AbstractProvider } from '@/modules/providers/shared/base/abstract.provider.js';
+import { CodexMcpProvider } from '@/modules/providers/list/codex/codex-mcp.provider.js';
+
+export class CodexProvider extends AbstractProvider {
+  readonly mcp = new CodexMcpProvider();
+
+  constructor() {
+    super('codex');
+  }
+}