Auth/Login improvements:
- Add dedicated login page (login_page.html)
- Redirect to /app after successful login/signup instead of welcome
- Add flash message categories to prevent cross-page message pollution
- Filter flash messages by category in templates
Exchange configuration fixes:
- Fix JS discarding API keys for public exchanges (now optional, not cleared)
- Add explicit key/secret validation in backend before saving
- Properly update configured_exchanges when keys provided
Trade dialog enhancements:
- Add exchange selector populated from connected exchanges
- Add testnet checkbox with exchange support detection
- Add production trading confirmation dialog
- Show TESTNET/LIVE badges on trade cards
- Validate exchange is configured before creating live trades
Bug fixes:
- Add try/except around get_user_data in is_logged_in()
- Fix DataFrame index access for user data retrieval
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
