Lemenzo Gallery v1.23 viewer rendering fix

- Replaces full-screen VideoView/SurfaceView playback with a TextureView + MediaPlayer player.
  This addresses the observed audio-playing/black-video-surface failure and keeps video in the
  regular view compositor with deterministic fit-center scaling.
- Removes the black background from the actual video rendering surface; black remains on the
  parent player container for letterboxing.
- Uses BitmapFactory as the primary decoder for common WhatsApp/download still formats
  (JPEG/PNG/BMP), with EXIF orientation correction, bounded sampling and ImageDecoder fallback.
- Retains ImageDecoder-first handling for modern formats such as HEIF/HEIC/AVIF/WebP.
- Adds a final drawable fallback for still images before showing a viewer error.
- Video player releases correctly on page changes, surface destruction and activity teardown.
- Viewer playback is paused/resumed with the activity lifecycle.

Runtime verification is still required on-device for the exact WhatsApp files that reproduced
the original issue.