Add AI assistant guidelines with mandatory testing requirements

This document establishes critical workflow rules to prevent untested code
from being committed. Key requirements:

- Read test files before making changes to understand expectations
- Verify all changes match what tests expect (button text, labels, etc)
- Run tests via Docker build before committing
- Never commit code that hasn't been verified to work

This should prevent issues like button text mismatches where the component
says "Access Dashboard" but tests expect "Sign In".

https://claude.ai/code/session_01T57NPQfoRb2fS7ihdWkTxq

CLAUDE.md

@@ -0,0 +1,93 @@
+# AI Assistant Guidelines for Docker Swarm Terminal
+
+## Critical Testing Requirements
+
+**NEVER commit code without verifying it works with the existing tests.**
+
+### Before Making Any Changes
+
+1. **Read the test files first** - Understand what the tests expect
+   - E2E tests: `frontend/e2e/*.spec.ts`
+   - Unit tests: `frontend/**/__tests__/*.test.tsx`
+
+2. **Understand the test expectations** - Check for:
+   - Button text and labels (e.g., tests expect "Sign In", not "Access Dashboard")
+   - Component structure and roles
+   - User interactions and flows
+
+### Testing Workflow
+
+When making changes to components or functionality:
+
+1. **Read the relevant test file(s)** before changing code
+   ```bash
+   # For login changes, read:
+   cat frontend/e2e/login.spec.ts
+   cat frontend/components/__tests__/LoginForm.test.tsx
+   ```
+
+2. **Make your changes** ensuring they match test expectations
+
+3. **Verify tests pass** by building the Docker test image:
+   ```bash
+   docker build --target test -t docker-swarm-terminal-test .
+   ```
+
+4. **Only commit if tests pass** - If tests fail, fix the code, don't change the tests
+
+### Common Mistakes to Avoid
+
+- ❌ Changing button text without checking what tests expect
+- ❌ Modifying component structure without verifying e2e selectors
+- ❌ Assuming tests will adapt to your changes
+- ❌ Committing without running tests
+
+### Test Structure
+
+- **Unit tests**: Test individual components in isolation
+- **E2E tests**: Test user workflows in Playwright
+  - Tests use `getByRole()`, `getByLabel()`, and `getByText()` selectors
+  - These selectors are case-insensitive with `/i` flag
+  - Button text must match exactly what tests query for
+
+### When Tests Fail
+
+1. **Read the error message carefully** - It shows exactly what's missing
+2. **Check the test file** - See what text/structure it expects
+3. **Fix the code to match** - Don't change tests unless they're genuinely wrong
+4. **Verify the fix** - Run tests again before committing
+
+## Development Commands
+
+```bash
+# Run all tests in Docker (CI environment)
+docker build --target test .
+
+# Run e2e tests locally (requires dependencies)
+cd frontend && npm run test:e2e
+
+# Run unit tests locally
+cd frontend && npm test
+
+# Run specific test file
+cd frontend && npm test -- LoginForm
+```
+
+## Project Structure
+
+- `frontend/` - Next.js application
+  - `components/` - React components
+  - `e2e/` - Playwright end-to-end tests
+  - `lib/hooks/` - Custom React hooks
+- `backend/` - Go backend service
+- `docker-compose.yml` - Local development setup
+- `Dockerfile` - Multi-stage build with test target
+
+## Git Workflow
+
+1. Always work on feature branches starting with `claude/`
+2. Commit messages should explain WHY, not just WHAT
+3. Push to the designated branch only
+4. Tests must pass in CI before merging
+
+Remember: **Code that doesn't pass tests is broken code.** Always verify before committing.