- Added `tzdata` installation in the Dockerfile to support time zone handling in Linux environments.
- Increased `PIP_DEFAULT_TIMEOUT` and added retry logic for pip installations to enhance reliability during dependency installation.
- Updated `requirements.txt` to conditionally include `tzdata` for Windows platforms, ensuring compatibility across different operating systems.
- Updated the exercise form to include a tabbed navigation structure, improving user experience with sections for Stammdaten, Anleitung, Einordnung, Varianten, and Medien & Mehr.
- Introduced the concept of **Freigabelevel** (visibility level) in the UI, replacing previous terminology for clarity and consistency across components.
- Implemented new AI endpoints for exercise suggestions and regeneration, allowing for dynamic content generation without direct database writes.
- Removed the legacy `is_primary` flag from exercise skills in the UI, ensuring that intensity levels (`niedrig`, `mittel`, `hoch`) are the primary focus for skill management.
- Enhanced the variant management process with improved saving mechanisms and UI updates to reflect changes more intuitively.
- Updated migration logic in main.py to allow skipping migrations during local development with SKIP_DB_MIGRATE environment variable.
- Improved error handling for migration failures, ensuring the application does not start if migrations are incomplete.
- Added a new health check endpoint (/api/health/ready) to verify database connection and essential tables, aiding in production debugging.
- Enhanced run_migrations.py to support ordered execution of migration files and improved transaction handling.
- Updated requirements.txt to include sqlparse for SQL statement parsing when psql is unavailable.
