ci: add concurrency + timeout-minutes to publish workflow

- concurrency group=publish with cancel-in-progress: false so back-to-back
  tag pushes queue rather than cancel a mid-publish (partial releases are
  worse than waiting)
- 15-minute timeout so a stuck publish doesn't hold the queue for 6h

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: vvillait88

.github/workflows/publish.yml

@@ -8,9 +8,14 @@ permissions:
   contents: write
   id-token: write
 
+concurrency:
+  group: publish
+  cancel-in-progress: false
+
 jobs:
   publish:
     runs-on: ubuntu-latest
+    timeout-minutes: 15
     steps:
       - uses: actions/checkout@v6