MCP SSE support (#511)

Matches the config format used by other MCP clients.

packages/server/src/config/config.ts

@@ -24,10 +24,14 @@ import { WebSearchTool } from '../tools/web-search.js';
 
 export class MCPServerConfig {
   constructor(
-    readonly command: string,
+    // For stdio transport
+    readonly command?: string,
     readonly args?: string[],
     readonly env?: Record<string, string>,
     readonly cwd?: string,
+    // For sse transport
+    readonly url?: string,
+    // Common
     readonly timeout?: number,
   ) {}
 }