Lemenzo Gallery v1.22 - media compatibility / viewer robustness

- Reworked full-screen still-image decoding to use a true two-stage pipeline:
  Android ImageDecoder first, then independent BitmapFactory fallback.
- Added bounded decode sizing for large images to reduce OOM risk.
- Added software allocation and partial-image acceptance for difficult/truncated downloads.
- Animated GIF/WebP now fall back to a robust still-frame decode when animated decode fails.
- Viewer no longer stays silently black when an image cannot be decoded; a localized error is shown.
- Video viewer now handles MediaPlayer/VideoView playback errors with a localized user-facing message.
- Existing MediaStore discovery, zoom, Ultra HDR detection, motion photo detection, editing and privacy flows remain intact.

Scope: Android-supported image/video formats and codecs available on the device. No gallery can decode a format or video codec that the platform itself has no decoder for.