Replace pip + requirements.txt with uv for dependency management.
- Multi-stage Dockerfile using ghcr.io/astral-sh/uv builder image
- CI updated to use astral-sh/setup-uv@v4
- Ruff config moved to [tool.ruff.lint] (fixes deprecation)
- Transitive deps removed, missing direct deps added (requests, PySocks, urllib3)
- Database layer migrated to async (AsyncSession + aiosqlite)
- Tests updated to match async database interface
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>