Add track publication, album types, optional track pictures and batch upload URLs

Tracks
- Track.IsPublished (migration marks existing tracks as published). New
  tracks are created unpublished.
- PUT /tracks/{id}/published and PUT /tracks/published change the flag;
  publishing requires completed audio processing (the batch endpoint
  reports skipped tracks).
- An unpublished track is only visible to its owner. A WherePublished /
  VisibleTo filter is applied to search, genres, listening history, last
  listened, likes, mixes, album and playlist contents and counts, recently
  listened albums, public user tracks, track details and stream tickets.
- isPublished is part of the track responses, GET /tracks/users/{userId}
  accepts a published filter and status-counts reports published and
  unpublished totals.
- CreateTrackRequest.pictureIntentId is optional: without it the track
  uses the album cover or the preset picture and no picture processing
  runs. CreateTrackResourcesEvent carries nullable picture fields, so
  queues must be drained before deploying.
- POST /tracks/upload-urls accepts an audios list and one optional picture
  shared by all of them, and returns an intent per file. The upload intent
  limits are raised so a batch fits.

Albums
- AlbumType (Album, EP, Single) on create, update and responses.
- CreateAlbumRequest.trackIds creates the album and links the tracks in a
  single save.

backend/Core/Musify.Application/Tracks/GetTracksByUserId.cs

@@ -13,7 +13,9 @@ namespace Musify.Application.Tracks
         string? Name,
         int PageNumber,
         int PageSize,
-        IReadOnlyList<ProcessingStatus>? Statuses = null)
+        IReadOnlyList<ProcessingStatus>? Statuses = null,
+        long? ViewerId = null,
+        bool? IsPublished = null)
         : IQuery<ErrorOr<PaginatedResponse<UserTrackApplicationResponse>>>;
 
     public class GetTracksByUserIdQueryHandler(IDatabase database)
@@ -26,6 +28,9 @@ namespace Musify.Application.Tracks
                 .Active()
                 .Where(track => track.OwnerUserId == request.UserId);
 
+            if (request.ViewerId != request.UserId)
+                tracksQuery = tracksQuery.WherePublished();
+
             if (!string.IsNullOrWhiteSpace(request.Name))
             {
                 var normalizedName = TextNormalizer.Normalize(request.Name);
@@ -38,6 +43,9 @@ namespace Musify.Application.Tracks
                 tracksQuery = tracksQuery.Where(track => statusList.Contains(track.Audio.TranscodeStatus));
             }
 
+            if (request.IsPublished is { } isPublished)
+                tracksQuery = tracksQuery.Where(track => track.IsPublished == isPublished);
+
             return await tracksQuery
                 .OrderByDescending(track => track.CreatedAt)
                 .ThenBy(track => track.Id)