fix: update serve:http to run main.ts instead of server.ts (#315)

After commit 65a62a9f, the server startup code was moved from server.ts
to main.ts, but the serve:http script was not updated accordingly.

This caused 9 example servers to fail to start when running npm start:
- budget-allocator-server
- cohort-heatmap-server
- customer-segmentation-server
- integration-server
- map-server
- scenario-modeler-server
- system-monitor-server
- threejs-server
- wiki-explorer-server

The server.ts file now only exports createServer(), while main.ts
contains the actual server startup logic.

examples/qr-server/server.py

@@ -27,7 +27,7 @@ WIDGET_URI = "ui://qr-server/widget.html"
 HOST = os.environ.get("HOST", "0.0.0.0")  # 0.0.0.0 for Docker compatibility
 PORT = int(os.environ.get("PORT", "3108"))
 
-mcp = FastMCP("QR Code Server", port=PORT, stateless_http=True)
+mcp = FastMCP("QR Code Server")
 
 
 @mcp.tool(meta={
@@ -92,7 +92,7 @@ if __name__ == "__main__":
         mcp.run(transport="stdio")
     else:
         # HTTP mode for basic-host (default) - with CORS
-        app = mcp.streamable_http_app()
+        app = mcp.streamable_http_app(stateless_http=True)
         app.add_middleware(
             CORSMiddleware,
             allow_origins=["*"],