Improve pyglet_image_loader with Tile Flipping Support and Robust Error Handling

[JaskRendix]

PR improves the pytmx integration with pyglet by upgrading the custom image loader function.

Key changes:

• added parsing and handling for tile flip and rotation flags via a new handle_flags() helper
• tiles are now transformed using get_transform() with support for horizontal, vertical, and diagonal flips
• rotation support introduced based on Tiled's diagonal flip semantics
• image resource path is now explicitly resolved with pathlib.Path, improving compatibility across environments
• improved error handling: specific exceptions are logged with detailed context using exc_info=True
• type annotations added for better clarity and static analysis support
• clean separation of concerns between image loading and flag processing logic