v1.2.1 - Add comprehensive symlink support

What's New

Symlink Support

• Full symlink preservation: Create, extract, and list symbolic links with complete metadata preservation
• Cross-platform compatibility: Works on Unix-like systems (Linux, macOS, BSD)
• All symlink types supported: Relative paths, absolute paths, broken links, and directory links
• Integration with existing features: Symlinks work seamlessly with compression (ZSTD) and encryption (ChaCha20-Poly1305)

API Enhancements

• New bfc_add_symlink() function for programmatic symlink creation
• Enhanced CLI commands to handle symlinks across all operations (create, extract, list, info, verify)
• Proper symlink detection using lstat() instead of stat()

CLI Improvements

• Create command: Automatically detects and preserves symlinks during container creation
• Extract command: Restores symlinks with original targets and timestamps using lutimes()
• List command: Displays symlinks with 'l' prefix in file mode (e.g., lrwxrwxrwx)
• Info command: Shows symlink count and type statistics
• Verify command: Validates symlink integrity and targets

Testing & Quality

• Comprehensive unit test coverage for both writer and reader functionality
• Integration tests covering all symlink scenarios
• CI/CD pipeline updated with symlink testing
• Cross-platform build fixes for Linux systems

Technical Details

• Symlink targets are stored as file content within the container format
• Uses existing BFC_TYPE_SYMLINK object type in the BFC format
• Maintains backward compatibility with existing containers
• CRC32C validation ensures symlink target integrity