test(cli): cover diff cli_utils path normalization and install detection

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Summary

Adds regression tests for pykotor.diff_tool.cli_utils, which was updated in the case-aware path work (#151) but had no direct test coverage.

Risky behavior now covered

• normalize_path_arg: PowerShell quoting edge cases (mangled " concatenation, embedded quotes, trailing backslashes) that break diff/patch CLI path inputs on Windows.
• is_kotor_install_dir: Case-aware install detection via chitin.key lookup — used by diff, patching, and TSLPatcher diff engine to route installation-vs-file comparisons.

Test files added/updated

• Libraries/PyKotor/tests/cli/test_diff_cli_utils.py (new, 15 tests)

Why these tests materially reduce regression risk

• All three is_kotor_install_dir implementations (cli_utils, patching, tslpatcher.diff.engine) are asserted in parallel so a future refactor cannot silently diverge.
• Case-mismatched install directory detection is covered on POSIX (skipped on Windows where semantics differ).
• normalize_path_arg parametrized cases lock in the quoting fixes that prevent CLI failures when users pass paths with spaces from PowerShell.

Validation

pytest Libraries/PyKotor/tests/cli/test_diff_cli_utils.py -v
# 15 passed

  

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