Security Improvements:
- Add input sanitization utilities (XSS, SQL injection prevention)
- Add token validation with JWT structure verification
- Add secure form validators with pattern enforcement
- Implement proper token storage with encryption support
Service Hardening:
- Add timeout (30s) and retry logic (3 attempts) to all API calls
- Add UUID validation for all ID parameters
- Add null/undefined checks with defensive defaults
- Proper error propagation with typed error handling
Component Fixes:
- Fix memory leaks with takeUntilDestroyed pattern
- Remove mock data fallbacks in error handlers
- Add proper loading/error state management
- Add form field length limits and validation
Files affected: 51 (6000+ lines added for security)
