test: add comprehensive ListFilesTool test suite (40 tests) (#213)

* test: add comprehensive ListFilesTool test suite (40 tests)

Add full test coverage for ListFilesTool including:
- Parameter validation (missing path)
- Basic and recursive file listing
- Approval flow and user cancellation
- Relative and absolute path resolution
- Error handling (nonexistent dirs, permission denied)
- Partial message streaming (handlePartial)
- Edge cases (empty dirs, large file sets, root/dot paths)
- Singleton instance verification
- RooIgnore/RooProtected controller passthrough

Fixes cross-platform compatibility for Windows CI by using
path.resolve() instead of hardcoded Unix paths, and removing
the unnecessary path module mock that caused failures on Windows.

Closes #209

* test(listFiles): assert consecutiveMistakeCount value on validation+error path

Addresses CodeRabbit review: the 'no reset on error' test never asserted the
counter, so it would pass even if the reset behavior regressed. Renamed to
reflect actual behavior (validation success resets to 0 before listFiles
throws) and added the missing assertion. 40 tests pass.

* test(listFilesTool): cover case-insensitive recursive flag instead of duplicate

* Update src/core/tools/__tests__/listFilesTool.spec.ts

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Co-authored-by: Armando Vaquera <263793884+proyectoauraorg@users.noreply.github.com>
Co-authored-by: edelauna <54631123+edelauna@users.noreply.github.com>

Author: proyectoauraorg