feat(mcp): add Model Context Protocol integration

Add  MCP integration including:
- New MCP settings tab with server configuration
- Tool invocation UI components
- API endpoints for MCP management
- Integration with chat system for tool execution
- Example configurations

package.json

@@ -51,6 +51,8 @@
     "@ai-sdk/google": "0.0.52",
     "@ai-sdk/mistral": "0.0.43",
     "@ai-sdk/openai": "1.1.2",
+    "@ai-sdk/react": "^1.2.12",
+    "@ai-sdk/ui-utils": "^1.2.11",
     "@codemirror/autocomplete": "^6.18.3",
     "@codemirror/commands": "^6.7.1",
     "@codemirror/lang-cpp": "^6.0.2",
@@ -71,6 +73,7 @@
     "@heroicons/react": "^2.2.0",
     "@iconify-json/svg-spinners": "^1.2.1",
     "@lezer/highlight": "^1.2.1",
+    "@modelcontextprotocol/sdk": "^1.15.0",
     "@nanostores/react": "^0.7.3",
     "@octokit/rest": "^21.0.2",
     "@octokit/types": "^13.6.2",