test: cover compact source normalization edge cases

[haosenwang1018]

Summary

• add direct coverage for ~/... expansion in _normalize_compact_source()
• verify non-path filters are returned unchanged instead of being resolved as filesystem paths
• keep the existing no-match compact CLI smoke test alongside the helper-level path normalization coverage

Testing

• uv run ruff format tests/test_compact_cli.py
• uv run ruff check tests/test_compact_cli.py
• uv run python -m pytest tests/test_compact_cli.py -q

Closes #114