Major Changes:
- Set up SQLx database connection and migration system
- Create complete initial database schema with all tables
- Rename 'auction' to 'listing' throughout codebase for better terminology
- Update bot commands: /newauction -> /newlisting, /myauctions -> /mylistings
- Update all database tables: auctions -> listings, auction_medias -> listing_medias
- Update foreign key relationships and indexes
- Add automatic database migration on startup
- Update documentation and README
- Complete backlog tasks: task-001, task-002, task-010
The bot now has a solid database foundation ready for implementing core business logic.
All tests pass and code compiles successfully.
