ci: add Claude PR review workflow

.github/workflows/claude-review.yml

@@ -0,0 +1,50 @@
+name: Claude PR Review
+
+on:
+  pull_request:
+    types: [opened, synchronize]
+  issue_comment:
+    types: [created]
+  pull_request_review_comment:
+    types: [created]
+  workflow_dispatch:
+
+concurrency:
+  group: claude-review-${{ github.event.pull_request.number || github.event.issue.number || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+  pull-requests: write
+  issues: write
+
+jobs:
+  review:
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    if: |
+      github.event_name == 'pull_request' ||
+      github.event_name == 'workflow_dispatch' ||
+      (github.event_name == 'issue_comment' &&
+       github.event.issue.pull_request &&
+       contains(github.event.comment.body, '@claude') &&
+       github.actor != 'claude[bot]') ||
+      (github.event_name == 'pull_request_review_comment' &&
+       contains(github.event.comment.body, '@claude') &&
+       github.actor != 'claude[bot]')
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Read review instructions
+        id: review
+        run: |
+          EOF=$(dd if=/dev/urandom bs=15 count=1 status=none | base64)
+          echo "instructions<<$EOF" >> "$GITHUB_OUTPUT"
+          cat REVIEW.md >> "$GITHUB_OUTPUT"
+          echo "$EOF" >> "$GITHUB_OUTPUT"
+
+      - uses: anthropics/claude-code-action@v1
+        with:
+          anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+          model: claude-sonnet-4-6
+          review_instructions: ${{ steps.review.outputs.instructions }}