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

app/types/context.ts

@@ -16,3 +16,11 @@ export type ProgressAnnotation = {
   order: number;
   message: string;
 };
+
+export type ToolCallAnnotation = {
+  type: 'toolCall';
+  toolCallId: string;
+  serverName: string;
+  toolName: string;
+  toolDescription: string;
+};