fix(lint): apply ruff formatting and remove unused imports

[blackaxgit]

Summary

• Applied ruff format to 6 files that failed the CI formatting check
• Removed 5 unused imports (tempfile, pytest, asyncio, MagicMock, Path)
• Fixed 1 unused variable assignment (registry) in test_config.py

Test plan

• ruff format --check src/ tests/ passes
• ruff check src/ tests/ passes
• All 151 tests pass