- Code was calling db.fetchall() and db.fetchone() but these methods didn't exist
- Add helper methods that execute query and return results
- Fixes template loading and other database operations
- Create schema.sql with Data Principle support (projects, sessions, loot)
- Implement DatabaseManager with connection pooling and WAL mode
- Add Decimal adapter for PED/PEC precision (Rule #4)
- Enable foreign keys and performance optimizations (Rule #3)
- Add backup functionality for data safety
Database supports project archiving, session tracking, and
historical data comparison per Data Principle.