Fix UnArchiver read-only file extraction issue

This PR addresses the issue where UnArchiver fails to extract files when the target file exists and is read-only.

Checklist:

• Understand the issue and codebase
• Run existing tests to verify current state
• Implement fix: Delete existing file before extracting (in extractFile method)
• Add test to verify read-only files can be overwritten during extraction
• Run tests to ensure no regressions (341 tests pass)
• Address code review feedback: Keep REPLACE_EXISTING as fallback
• Fix Windows compatibility: Make file writable before delete
• All tests pass (32 UnArchiver tests)

Summary:

The issue occurs in AbstractUnArchiver.extractFile() where Files.copy with REPLACE_EXISTING may fail on read-only files on some platforms. The fix deletes the existing file before copying, similar to how tar and unzip handle this scenario.

Changes Made:

1. Modified AbstractUnArchiver.extractFile() to delete the existing file before calling Files.copy()
2. Added setWritable(true) before delete() to handle Windows where read-only files cannot be deleted
3. Kept REPLACE_EXISTING as a fallback for robustness (belt and suspenders approach)
4. Added a test case shouldExtractReadOnlyFile() to verify the fix works correctly
5. All tests pass successfully

Implementation Details:

The solution uses a robust approach:

• First, make the file writable (required on Windows for read-only files)
• Then, delete the existing file (handles read-only files on all platforms)
• Finally, copy with REPLACE_EXISTING flag (handles edge cases where delete might fail)

This provides maximum compatibility across different platforms (Linux, macOS, Windows) and permission scenarios.

• Fixes UnArchiver fails to extract files if the target exists and is read-only #138

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