docs: add protection lease webhook trigger events

Add clone_protection_expiring and clone_protection_expired webhook
trigger types to the configuration reference.

https://claude.ai/code/session_011sPDgBjzL2N2X6jiYyoTjQ

Author: claude

docs/reference-guides/database-lab-engine-configuration-reference.md

@@ -445,6 +445,8 @@ Webhooks provide a way to notify external systems about clone lifecycle events.
     - `clone_create` - triggered when a new clone is created
     - `clone_reset` - triggered when an existing clone is reset to a different snapshot
     - `clone_delete` - triggered when a clone is deleted. Supported since DBLab Engine 4.1.
+    - `clone_protection_expiring` - triggered when a clone's protection lease is about to expire (based on `protectionExpiryWarningMinutes`). Supported since DBLab Engine 4.1.
+    - `clone_protection_expired` - triggered when a clone's protection lease has expired and protection has been automatically removed. Supported since DBLab Engine 4.1.
 
 ### Webhook payload format
 Webhook requests are sent as HTTP POST with JSON payload containing: