fix: exclude Python from AppImage to fix Show In Folder with non-ASCII paths #1885

The AppImage bundles Python with a non-standard prefix (usr/bin), causing AppRun to set PYTHONHOME={AppImage}/usr/bin. External tools invoked by Shotcut (e.g. xdg-open for "Show In Folder") inherit this env var and fail when the path contains non-ASCII characters: Could not parse arguments: Invalid byte sequence in conversion input.

• 
  packaging/linux/appimage/appimage.yml: Remove Python from the AppDir after tarball extraction. Covers the non-standard prefix location (usr/bin/lib/python*) and the standard one (usr/lib/python*):
  yaml
- rm -rf usr/bin/python* usr/bin/lib/python* usr/lib/python*

  With no Python in the AppDir, AppRun does not set PYTHONHOME/PYTHONPATH, and external processes handle all paths correctly.