Avoid false junction detection from drive-letter case

[Mirochill]

Fixes #208.

Summary

• compare Windows link paths as Path objects instead of stringifying them
• add a regression for drive-letter-only case differences when checking junctions

Validation

• git diff --check
• git show --check --stat --oneline HEAD
• Not run locally.
• Remote: pre-commit.ci passed.
• Remote: GitHub Actions are blocked before project tests or analysis. CodeQL and the Test MicropyCli jobs fail during setup with Poetry reporting pyproject.toml changed significantly since poetry.lock was last generated; macOS-12 Test MicropyCli jobs were later cancelled after remaining queued.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.82%. Comparing base (49c7f75) to head (4ec164a).
⚠️ Report is 32 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #637      +/-   ##
==========================================
+ Coverage   91.36%   91.82%   +0.46%     
==========================================
  Files          50       52       +2     
  Lines        2756     2827      +71     
==========================================
+ Hits         2518     2596      +78     
+ Misses        238      231       -7     

Flag	Coverage Δ
os-macos-latest	91.79% <100.00%> (?)
os-ubuntu-latest	91.79% <100.00%> (?)
os-windows-latest	91.25% <100.00%> (-0.12%)	⬇️
py-3.10	91.79% <100.00%> (+2.60%)	⬆️
py-3.11	91.79% <100.00%> (+2.60%)	⬆️
py-3.9	91.78% <100.00%> (+0.46%)	⬆️
unittests	91.82% <100.00%> (+0.46%)	⬆️

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