- Fix import in test_db_utils.py: use app.models instead of backend.app.models
- Update health endpoint test to expect 'ok' status and infrastructure keys
- Add CHANGELOG entries for PyPI proxy performance improvements
Add optimized database operations for artifact storage:
- Atomic upserts using ON CONFLICT for artifact creation
- Batch inserts for dependencies to eliminate N+1 queries
- Joined queries for cached URL lookups
- All methods include comprehensive unit tests