Remove remote scripts and files dependency

[magicoli]

Implement playlists and video editing server-side, to remove the need
for manual rules files editing and synchronizing.

Tasks

• Extract video conversion, merge, thumbnails and naming logic from shell script
• Visual video merge and naming
• Visual playlist tool (display order, sections...)
• Background video conversion (optional use of an external service)
• Implement proper error handling and logging
• Add progress tracking for large directory operations
• Deploy independently - fixes current sync issues