feat: add Claude Code GitHub Action for @claude mentions

Enable @claude mention bot in issues and PRs. When users mention @claude,
the action will automatically respond with AI assistance for:
- Code review and analysis
- Answering technical questions
- Implementing features
- Creating pull requests
- Bug fixes and refactoring

Requires ANTHROPIC_API_KEY secret to be configured in repository settings.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: jeremyeder

.github/workflows/claude-code-action.yml

@@ -0,0 +1,26 @@
+name: Claude Code Action
+
+on:
+  issue_comment:
+    types: [created]
+  pull_request_review_comment:
+    types: [created]
+  issues:
+    types: [opened, assigned]
+  pull_request:
+    types: [opened, ready_for_review]
+
+permissions:
+  contents: write
+  pull-requests: write
+  issues: write
+
+jobs:
+  claude-code:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Claude Code Action
+        uses: anthropics/claude-code-action@v1
+        with:
+          anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+          github_token: ${{ secrets.GITHUB_TOKEN }}