Add concurrency group and bot filter to Claude Code workflow

- Add concurrency group to cancel in-progress reviews on the same PR
  when a new push arrives (avoids duplicate reviews from rapid pushes)
- Filter out bot comments from @claude trigger to prevent infinite loops

Co-authored-by: Isaac

Author: shreyas-goenka

.github/workflows/claude-code.yml

@@ -21,6 +21,9 @@ jobs:
   # Automatic PR review when a PR is opened or updated.
   review:
     if: github.event_name == 'pull_request'
+    concurrency:
+      group: claude-review-${{ github.event.pull_request.number }}
+      cancel-in-progress: true
     runs-on:
       group: databricks-deco-testing-runner-group
       labels: ubuntu-latest-deco
@@ -51,8 +54,11 @@ jobs:
   # Interactive @claude mentions.
   assist:
     if: |
-      (github.event_name == 'issue_comment' && contains(github.event.comment.body, '@claude')) ||
-      (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '@claude'))
+      github.event.comment.user.type != 'Bot' &&
+      (
+        (github.event_name == 'issue_comment' && contains(github.event.comment.body, '@claude')) ||
+        (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '@claude'))
+      )
     runs-on:
       group: databricks-deco-testing-runner-group
       labels: ubuntu-latest-deco