Track cancelled deployments separately.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/common/enums.ts

@@ -72,6 +72,7 @@ export enum DeploymentStatus {
   DEPLOYING = 'deploying',
   RUNNING = 'running',
   FAILED = 'failed',
+  CANCELLED = 'cancelled',
   STOPPED = 'stopped',
   DELETING = 'deleting',
 }