Add concurrency group to prevent duplicate sync runs

Co-authored-by: devlux76 <[email protected]>

Author: Copilot

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

@@ -8,6 +8,10 @@ on:
       - "TODO.md"
   workflow_dispatch:
 
+concurrency:
+  group: sync-github-project
+  cancel-in-progress: false
+
 permissions:
   issues: write
   contents: read