server: actually invoke start() so dev/start scripts boot the server

The entry point defined and exported start() but never called it, so
running 'node --import tsx src/index.ts' imported the module and exited
0 without ever calling app.listen. Add a top-level start().catch() so the
server binds and logs its listen addresses.

server/src/index.ts

@@ -73,3 +73,8 @@ export async function start() {
   await app.listen({ port: config.port, host: "0.0.0.0" });
   return app;
 }
+
+start().catch((err) => {
+  console.error("Failed to start server:", err);
+  process.exit(1);
+});