fix: harden CCS backlog sync pagination and recovery

.github/workflows/sync-ccs-backlog-project.yml

@@ -12,6 +12,10 @@ on:
   schedule:
     - cron: '17 3 * * *'
 
+concurrency:
+  group: sync-ccs-backlog-project
+  cancel-in-progress: false
+
 permissions:
   contents: read
   issues: read