feat: serve React SPA from Fastify in production mode

apps/api/src/plugins/static.ts

@@ -0,0 +1,31 @@
+import type { FastifyInstance } from "fastify";
+import fastifyStatic from "@fastify/static";
+import { resolve, dirname } from "node:path";
+import { existsSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+
+export async function registerStatic(app: FastifyInstance) {
+  // Resolve relative to this file's location
+  const __dirname = dirname(fileURLToPath(import.meta.url));
+  const webDistPath = resolve(__dirname, "../../../web/dist");
+
+  if (!existsSync(webDistPath)) {
+    app.log.warn(`SPA dist not found at ${webDistPath} — skipping static file serving`);
+    return;
+  }
+
+  await app.register(fastifyStatic, {
+    root: webDistPath,
+    prefix: "/",
+    wildcard: false,
+  });
+
+  // SPA fallback — serve index.html for all non-API routes
+  app.setNotFoundHandler((request, reply) => {
+    if (request.url.startsWith("/api/")) {
+      reply.code(404).send({ error: "Not found", code: "NOT_FOUND" });
+    } else {
+      reply.sendFile("index.html");
+    }
+  });
+}