Architecture updates:
- Add EmailService documentation with config and flow diagram
- Update CVHandler struct to show all dependencies
- Add new middleware components (BrowserOnly, RateLimiter, etc.)
- Update package structure to include services, pdf, validation
New unit tests for HandleContact (9 tests):
- Valid submission
- Missing email/message validation
- Honeypot bot protection
- Timing-based bot protection (too fast)
- Invalid HTTP method (405)
- Invalid email format
- Message too short
- Spanish language support
Includes MockEmailService for isolated testing.