Add Claude Code GitHub Workflow (#1541)

## 🤖 Installing Claude Code GitHub App

This PR adds a GitHub Actions workflow that enables Claude Code
integration in our repository.

### What is Claude Code?

[Claude Code](https://claude.ai/code) is an AI coding agent that can
help with:
- Bug fixes and improvements  
- Documentation updates
- Implementing new features
- Code reviews and suggestions
- Writing tests
- And more!

### How it works

Once this PR is merged, we'll be able to interact with Claude by
mentioning @claude in a pull request or issue comment.
Once the workflow is triggered, Claude will analyze the comment and
surrounding context, and execute on the request in a GitHub action.

### Important Notes

- **This workflow won't take effect until this PR is merged**
- **@claude mentions won't work until after the merge is complete**
- The workflow runs automatically whenever Claude is mentioned in PR or
issue comments
- Claude gets access to the entire PR or issue context including files,
diffs, and previous comments

### Security

- Our Anthropic API key is securely stored as a GitHub Actions secret
- Only users with write access to the repository can trigger the
workflow
- All Claude runs are stored in the GitHub Actions run history
- Claude's default tools are limited to reading/writing files and
interacting with our repo by creating comments, branches, and commits.
- We can add more allowed tools by adding them to the workflow file
like:

```
allowed_tools: Bash(npm install),Bash(npm run build),Bash(npm run lint),Bash(npm run test)
```

There's more information in the [Claude Code action
repo](https://github.com/anthropics/claude-code-action).

After merging this PR, let's try mentioning @claude in a comment on any
PR to get started!

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
  * Introduced automated code review using Claude AI for pull requests.
* Added Claude AI code assistance, triggered by comments containing
"@claude" in issues and pull requests.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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

@@ -0,0 +1,78 @@
+name: Claude Code Review
+
+on:
+  pull_request:
+    types: [opened, synchronize]
+    # Optional: Only run on specific file changes
+    # paths:
+    #   - "src/**/*.ts"
+    #   - "src/**/*.tsx"
+    #   - "src/**/*.js"
+    #   - "src/**/*.jsx"
+
+jobs:
+  claude-review:
+    # Optional: Filter by PR author
+    # if: |
+    #   github.event.pull_request.user.login == 'external-contributor' ||
+    #   github.event.pull_request.user.login == 'new-developer' ||
+    #   github.event.pull_request.author_association == 'FIRST_TIME_CONTRIBUTOR'
+    
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+      issues: read
+      id-token: write
+    
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+
+      - name: Run Claude Code Review
+        id: claude-review
+        uses: anthropics/claude-code-action@beta
+        with:
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+
+          # Optional: Specify model (defaults to Claude Sonnet 4, uncomment for Claude Opus 4)
+          # model: "claude-opus-4-20250514"
+          
+          # Direct prompt for automated review (no @claude mention needed)
+          direct_prompt: |
+            Please review this pull request and provide feedback on:
+            - Code quality and best practices
+            - Potential bugs or issues
+            - Performance considerations
+            - Security concerns
+            - Test coverage
+            
+            Be constructive and helpful in your feedback.
+
+          # Optional: Use sticky comments to make Claude reuse the same comment on subsequent pushes to the same PR
+          # use_sticky_comment: true
+          
+          # Optional: Customize review based on file types
+          # direct_prompt: |
+          #   Review this PR focusing on:
+          #   - For TypeScript files: Type safety and proper interface usage
+          #   - For API endpoints: Security, input validation, and error handling
+          #   - For React components: Performance, accessibility, and best practices
+          #   - For tests: Coverage, edge cases, and test quality
+          
+          # Optional: Different prompts for different authors
+          # direct_prompt: |
+          #   ${{ github.event.pull_request.author_association == 'FIRST_TIME_CONTRIBUTOR' && 
+          #   'Welcome! Please review this PR from a first-time contributor. Be encouraging and provide detailed explanations for any suggestions.' ||
+          #   'Please provide a thorough code review focusing on our coding standards and best practices.' }}
+          
+          # Optional: Add specific tools for running tests or linting
+          # allowed_tools: "Bash(npm run test),Bash(npm run lint),Bash(npm run typecheck)"
+          
+          # Optional: Skip review for certain conditions
+          # if: |
+          #   !contains(github.event.pull_request.title, '[skip-review]') &&
+          #   !contains(github.event.pull_request.title, '[WIP]')
+

.github/workflows/claude.yml

@@ -0,0 +1,64 @@
+name: Claude Code
+
+on:
+  issue_comment:
+    types: [created]
+  pull_request_review_comment:
+    types: [created]
+  issues:
+    types: [opened, assigned]
+  pull_request_review:
+    types: [submitted]
+
+jobs:
+  claude:
+    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_name == 'pull_request_review' && contains(github.event.review.body, '@claude')) ||
+      (github.event_name == 'issues' && (contains(github.event.issue.body, '@claude') || contains(github.event.issue.title, '@claude')))
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+      issues: read
+      id-token: write
+      actions: read # Required for Claude to read CI results on PRs
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+
+      - name: Run Claude Code
+        id: claude
+        uses: anthropics/claude-code-action@beta
+        with:
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+
+          # This is an optional setting that allows Claude to read CI results on PRs
+          additional_permissions: |
+            actions: read
+          
+          # Optional: Specify model (defaults to Claude Sonnet 4, uncomment for Claude Opus 4)
+          # model: "claude-opus-4-20250514"
+          
+          # Optional: Customize the trigger phrase (default: @claude)
+          # trigger_phrase: "/claude"
+          
+          # Optional: Trigger when specific user is assigned to an issue
+          # assignee_trigger: "claude-bot"
+          
+          # Optional: Allow Claude to run specific commands
+          # allowed_tools: "Bash(npm install),Bash(npm run build),Bash(npm run test:*),Bash(npm run lint:*)"
+          
+          # Optional: Add custom instructions for Claude to customize its behavior for your project
+          # custom_instructions: |
+          #   Follow our coding standards
+          #   Ensure all new code has tests
+          #   Use TypeScript for new files
+          
+          # Optional: Custom environment variables for Claude
+          # claude_env: |
+          #   NODE_ENV: test
+