add shared resources directory

shared/config.ts

@@ -0,0 +1,5 @@
+// Single source of truth for the three service ports (dev/build-time only,
+// used by the Hono proxy). Runtime URLs are set via env (see proxy/src/env.ts).
+export const FRONTEND_PORT = "2080";
+export const PROXY_PORT = "3456";
+export const PB_PORT = "8090";