Bundled pre-existing changes on the branch:
- Video merge: controller, service, admin merge modal, and a repair
console command; new video_redirects table (with source_folder)
so merged/moved videos keep resolving under their old keys.
- Default avatar SVG for users without a profile picture.
- Assorted view tweaks across profile, video actions/comments/insights,
admin layout, video-details, and the app layout.
- Small touch-ups in SuperAdminController, User model, NasSyncService.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
