Titles were capped at 50 characters and the YouTube provisioner silently cut
them there, which mangles anything with a feature or a remix suffix. Albums
are about to make that far more visible, so the column now holds 200.
- Move all .NET (6 projects, solution, Directory.*.props, nuget.config)
into backend/ so the monorepo root can host non-.NET projects later
- Remove throwaway test artifacts: player.html, pl.json
- Trim dead Flutter rules from .gitignore
Build from backend/Musify.slnx: 0 warnings, 0 errors.