Adapt the refactored web player to the new backend API (id path params,
bulk track adds, flat list items, mix kind) and port AddAlbumToPlayList
to the backend conventions.
Guid and long route constraints, id/trackId parameter names, Update*Request without the New prefix,
sentence-case operation summaries, shared security scheme id and a single Limits class.
Following lists are public; followers are visible to the user and to mutual followers.
Adds GET /users/{id}/followers and /following, exposes isFollowing and canViewFollowers
on the profile, and returns isFollowedByViewer from user search so the web player no
longer calls /is-following per user.
Moves the login screen from /login to /auth, logout from /logout to
/auth/logout (alongside the existing /auth/login and /auth/callback
endpoints), and the public profile route from /u/[id] to /user/[id].
AUTH_REDIRECT_URI and AUTH_POST_LOGOUT_URI already point at
/auth/callback and / respectively, so no Zitadel config change is
needed for the auth move.
Admin