feat: minimal prod compose with watchtower auto-updates

frontend/vite.config.ts

@@ -12,4 +12,14 @@ export default defineConfig({
       },
     },
   },
+  preview: {
+    port: 3000,
+    proxy: {
+      "/api": {
+        // Overridable at container start (prod compose: http://app:8000).
+        target: process.env.VITE_API_PROXY_TARGET ?? "http://localhost:8000",
+        changeOrigin: true,
+      },
+    },
+  },
 });