Add encryption and setup wizard features

ENCRYPTION:
- Add cryptography library for secure storage
- Implement Fernet encryption for sensitive settings
- Key derived from SESSION_SECRET
- Auto-encrypt/decrypt transparent to app
- "enc:" prefix identifies encrypted values
- Graceful fallback if crypto unavailable

SETUP WIZARD:
- Detect fresh installs needing configuration
- 3-step wizard: Infrastructure, Security, AI Services
- "/" redirects to wizard if setup required
- Auto-generate session_secret option
- Skip option for advanced users
- Beautiful UI with progress indicators

UI IMPROVEMENTS:
- Enhanced sensitive field display
- Lock icon showing encryption status
- Improved show/hide toggle for passwords
- Better visual hierarchy

FILES:
- app/utils/encryption.py - Encryption utilities
- app/utils/setup_wizard.py - Wizard detection logic
- app/views/wizard.py - Wizard routes
- frontend/templates/setup_wizard.html - Wizard UI
- requirements.txt - Added cryptography
- IMPLEMENTATION_CHECKLIST.md - Status tracking

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

requirements.txt

@@ -4,6 +4,7 @@ celery  # Task queue
 redis  # Message broker for Celery
 sqlalchemy  # Database ORM
 pydantic  # Data validation
+cryptography>=41.0.0  # Encryption for sensitive settings in database
 openai  # GPT integration for metadata extraction
 PyPDF2>=3.0.0  # PDF processing for text extraction, metadata editing and rotation (replaces PyMuPDF)
 requests  # HTTP client