fix(player): align visible video preview controls

[kcng0]

Summary

• use the shared video gesture surface in Visible gallery previews
• match Invisible playback controls, settings, fit modes, orientation, and Back behavior
• support long-press 2x fast-forward with release/cancel restoration
• keep the change Dart-only for a Shorebird patch

Verification

• flutter analyze lib/presentation/visible/gallery_preview_screen.dart lib/presentation/player/video_player_surface.dart lib/presentation/player/video_player_controls.dart
• flutter test test/widget/video_player_controls_test.dart test/widget/player_screen_back_test.dart test/widget/viewer_screen_back_test.dart

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