Add CLAUDE.MD context file for AI development

CLAUDE.MD

@@ -0,0 +1,91 @@
+# Reflex Web - Development Guide
+
+## Running the App
+
+```bash
+# Install dependencies
+uv sync
+
+# Run development server
+reflex run
+
+# Open browser at http://localhost:3000
+```
+
+## Testing
+
+```bash
+# Run unit tests
+pytest
+
+# Run integration tests (requires Playwright)
+pytest tests/test_*.py
+
+# Run pre-commit checks
+pre-commit run --all-files
+
+# Run linting
+ruff check .
+
+# Run formatting
+ruff format .
+```
+
+## PR Submission Guidelines
+
+### Before Submitting
+
+1. **Run tests**: Ensure all tests pass locally
+2. **Run linting**: `ruff check .` should pass with no errors
+3. **Run formatting**: `ruff format .` to auto-format code
+4. **Test locally**: Run `reflex run` and verify your changes work
+
+### Commit Message Format
+
+```
+Brief description of change (50 chars or less)
+
+Longer explanation if needed. Describe what changed and why.
+
+Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
+```
+
+### PR Title and Description
+
+- **Title**: Clear, concise description (e.g., "Fix mobile navigation menu", "Add dark mode support to docs")
+- **Description**: Include:
+  - Summary of changes
+  - Why the change was needed
+  - Test plan or steps to verify
+  - Any relevant issue numbers
+
+### Example PR Description
+
+```markdown
+## Summary
+- Fixed rendering issue on the Base Vars documentation page
+- Updated component styling for better mobile responsiveness
+
+## Test Plan
+- [x] Verified page renders correctly on desktop
+- [x] Tested on mobile devices (iOS Safari, Chrome Android)
+- [x] All unit tests pass
+- [x] Linting passes
+
+🤖 Generated with [Claude Code](https://claude.com/claude-code)
+```
+
+### CI Requirements
+
+Your PR must pass:
+- Unit tests
+- Integration tests
+- Linting checks (Ruff)
+- Spell checking (Codespell)
+
+### Getting PR Approved
+
+- PRs are reviewed by the Reflex team
+- Address any review comments
+- Keep PRs focused on a single change when possible
+- Add screenshots for UI changes