fix(agent): increase dev server readiness probe timeout to 300s to accommodate slow Next.js cold boots and prevent premature AI loop restarts

vibn-frontend/lib/dev-container.ts

@@ -722,13 +722,13 @@ export async function probeDevServerReadiness(
   port: number,
 ): Promise<void> {
   await ensureDevServersTable();
-  // Up to ~120s: Next/Vite cold compile often exceeds 60s on small hosts.
+  // Up to ~300s: Next/Vite cold compile + potential npm installs can take a while.
   // We accept any HTTP response (including 404/500) as "listening" — only
   // connection failures stay 000 — because `curl -sf` falsely failed when `/`
   // returned a dev error page before the app was fully ready.
   const probeCmd =
     `last_code=000; ` +
-    `for i in $(seq 1 120); do ` +
+    `for i in $(seq 1 300); do ` +
     `for path in / ''; do ` +
     `code=$(curl -sS -o /dev/null -w '%{http_code}' --max-time 2 --connect-timeout 2 ` +
     `"http://127.0.0.1:${port}$path" 2>/dev/null || printf '000'); ` +
@@ -737,15 +737,15 @@ export async function probeDevServerReadiness(
     `done; ` +
     `sleep 1; done; ` +
     `echo "PROBE_FAIL last_code=$last_code port=${port}"; ` +
-    `echo "PROBE_FAIL ps=$(ps aux | grep -E 'node|npm|next|vite' | grep -v grep | head -3 | tr '\n' '|')"; ` +
-    `echo "PROBE_FAIL log_tail=$(tail -20 /var/log/vibn-dev/${serverId}.log 2>/dev/null | tr '\n' '|' | head -c 2000)"; ` +
+    `echo "PROBE_FAIL ps=$(ps aux | grep -E 'node|npm|next|vite' | grep -v grep | head -3 | tr '\\n' '|')"; ` +
+    `echo "PROBE_FAIL log_tail=$(tail -20 /var/log/vibn-dev/${serverId}.log 2>/dev/null | tr '\\n' '|' | head -c 2000)"; ` +
     `exit 1`;
 
   try {
     const r = await execInDevContainer({
       projectId,
       command: probeCmd,
-      timeoutMs: 130_000,
+      timeoutMs: 310_000,
     });
     if (r.exitCode === 0) {
       await query(