fix(GRO-2652): start server before initAuth; retry auth init on ECONNRESET

Previously: await initAuth() was a top-level ESM await. Any boot-time
ECONNRESET from Postgres propagated as an uncaught module-evaluation
error and killed the process before the server even started.

Now:
- serve() starts immediately so /health and public routes are available
- initAuth() runs in a retry loop (up to 10 attempts, exponential
  500 ms → 30 s); a permanent failure degrades to 503 on auth routes
  (existing catch-to-503 in authRouter) rather than crashing the pod

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/index.ts

@@ -292,14 +292,34 @@ api.route("/search", searchRouter);
 api.route("/buffer-rules", bufferRulesRouter);
 api.route("/routes", routesRouter);
 
+// Start the HTTP server first so /health and public routes are available immediately.
+// Auth initialization runs afterward with retry — a transient DB ECONNRESET at boot
+// must not crash the process (GRO-2652). Auth routes return 503 until initAuth succeeds.
 const port = Number(process.env.PORT ?? 3000);
-await initAuth();
-console.log(`API server listening on port ${port}`);
 const server = serve({ fetch: app.fetch, port });
+console.log(`API server listening on port ${port}`);
 
 // Start background reminder scheduler (runs every minute to check for upcoming appointments)
 startReminderScheduler();
 
+let initAttempt = 0;
+while (true) {
+  try {
+    await initAuth();
+    break;
+  } catch (err) {
+    initAttempt++;
+    const delay = Math.min(2 ** initAttempt * 500, 30_000);
+    console.error(`[auth] initAuth attempt ${initAttempt} failed: ${err}`);
+    if (initAttempt >= 10) {
+      console.error("[auth] auth init permanently failed — auth endpoints will serve 503");
+      break;
+    }
+    console.error(`[auth] retrying in ${delay}ms`);
+    await new Promise((r) => setTimeout(r, delay));
+  }
+}
+
 function shutdown() {
   console.log("Shutting down gracefully...");
   // SIGTERM/SIGINT → server.close() → callback → process.exit(0)