feat(worker): add autosync scheduler, endpoint, locking and UI controls

README.md

@@ -63,7 +63,9 @@ values ('<agency_uuid>', '<auth_user_uuid>', 'owner');
 
 - `POST /api/plesk/instances` — create + validate Plesk connection
 - `POST /api/plesk/instances/:id/sync` — pull/sync subscriptions + domains from one Plesk instance
+- `POST /api/plesk/instances/:id/autosync` — update auto-sync enabled/frequency for one Plesk instance
 - `POST /api/jobs/plesk-sync-all` — background sync job for all connected instances (requires `X-JOB-SECRET`)
+- `POST /api/cron/autosync` — scheduled auto-sync tick (requires `X-CRON-SECRET`)
 - `POST /api/plesk/subscriptions/:id/action` — suspend or unsuspend
 - `POST /api/stripe/checkout` — create Stripe Checkout session
 - `POST /api/stripe/portal` — create Stripe Customer Portal session
@@ -74,6 +76,7 @@ values ('<agency_uuid>', '<auth_user_uuid>', 'owner');
 - Set a strong `ENCRYPTION_KEY`; it encrypts stored Plesk auth secrets.
 - Set a strong `PLESK_CRED_ENC_KEY` (32-byte base64 or 64-char hex) for Plesk credential encryption.
 - Set `JOB_SECRET` for internal cron-triggered job auth.
+- Set `CRON_SECRET` for `/api/cron/autosync` auth.
 - `/api/stripe/webhook` is excluded from auth middleware for Stripe signature verification.
 - Current implementation is intentionally MVP-focused; add stronger validation, retries, idempotency keys, and richer error observability for production.
 
@@ -97,3 +100,37 @@ Notes:
 - Job uses DB lock (`job_locks`) to avoid overlapping runs.
 - Job processes at most 10 connected instances per run.
 - Instances synced in the last 3 minutes are skipped.
+
+## 6) Auto Sync Worker (CL6)
+
+New scheduler fields live on `plesk_instances`:
+
+- `auto_sync_enabled`
+- `auto_sync_frequency_minutes`
+- `last_auto_sync_at`
+- `next_auto_sync_at`
+- `auto_sync_lock_until`
+- `auto_sync_lock_token`
+
+Endpoint for periodic worker ticks:
+
+```bash
+curl -sS -X POST http://localhost:3000/api/cron/autosync \
+  -H "X-CRON-SECRET: <CRON_SECRET>"
+```
+
+Recommended system cron (every 5 minutes):
+
+```cron
+*/5 * * * * curl -sS -X POST https://<your-host>/api/cron/autosync -H "X-CRON-SECRET: ${CRON_SECRET}"
+```
+
+Or schedule the same call from Jenkins.
+
+Worker safety behavior:
+
+- processes at most 5 instances per tick
+- concurrency limited to 2 at a time
+- per-instance lock lease 15 minutes
+- per-instance timeout guard 14 minutes
+- per-instance failures are isolated and logged to `actions_log`