Add automated Windows path normalization tests for spec.match_file()

[chigwell]

User Story
As a maintainer,
I want automated tests for Windows path normalization in spec.match_file()
so that cross-platform behavior is verified and regressions are prevented.

Background
The scan_directory function uses pathspec for OS-agnostic path matching, but the current test suite lacks validation for Windows-style paths (e.g., backslashes). This creates risks:

• Path normalization logic in scanner.py (lines 9–14) may behave unexpectedly on Windows
• Undetected mismatches between Unix-style ignore patterns and Windows paths
• Silent failures when deploying the tool in mixed-OS environments

Acceptance Criteria

• Create tests/unit/test_path_normalization.py with Windows path test cases
• Test both normalized (POSIX-style) and raw Windows paths in spec.match_file():

  # Example test case
  assert spec.match_file("C:\\Users\\Project\\tmp\\file.log") == True  # For pattern "tmp/*"

• Verify path normalization handles:
  • Backslashes in input paths
  • Mixed casing (Windows case-insensitivity)
  • Network paths (e.g., \\server\share\file.txt)
• Add Windows runner to CI/CD (GitHub Actions or similar)
• Update README.md Testing section to mention Windows compatibility verification

Validation

• Run test suite on Windows machine and confirm 100% pass rate
• Confirm CI pipeline executes Windows-specific tests
• Check debug logs during tests for correct path normalization output