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  tracks are created unpublished.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- An unpublished track is only visible to its owner.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  unpublished totals.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/Hosts/Musify.Api/Validators/Albums/CreateAlbumRequestValidator.cs

@@ -5,6 +5,8 @@ namespace Musify.Api.Validators.Albums
 {
     public sealed class CreateAlbumRequestValidator : AbstractValidator<CreateAlbumRequest>
     {
+        public const int MaxTracksOnCreate = 500;
+
         public CreateAlbumRequestValidator()
         {
             RuleFor(x => x.Title)
@@ -20,6 +22,18 @@ namespace Musify.Api.Validators.Albums
 
             RuleFor(x => x.PictureIntentId)
                 .NotEmpty();
+
+            RuleFor(x => x.Type)
+                .IsInEnum();
+
+            RuleFor(x => x.TrackIds)
+                .Must(ids => ids!.Count <= MaxTracksOnCreate)
+                .WithMessage($"At most {MaxTracksOnCreate} tracks can be added at once.")
+                .When(x => x.TrackIds != null);
+
+            RuleForEach(x => x.TrackIds)
+                .NotEmpty()
+                .When(x => x.TrackIds != null);
         }
     }
 }

backend/Hosts/Musify.Api/Validators/Albums/UpdateAlbumRequestValidator.cs

@@ -17,6 +17,10 @@ namespace Musify.Api.Validators.Albums
             RuleFor(x => x.ReleaseYear)
                 .InclusiveBetween(Limits.EarliestReleaseYear, Limits.LatestReleaseYear)
                 .When(x => x.ReleaseYear.HasValue);
+
+            RuleFor(x => x.Type)
+                .IsInEnum()
+                .When(x => x.Type.HasValue);
         }
     }
 }

backend/Hosts/Musify.Api/Validators/Tracks/CreateTrackRequestValidator.cs

@@ -13,7 +13,8 @@ namespace Musify.Api.Validators.Tracks
                 .MaximumLength(Limits.TrackTitle);
 
             RuleFor(x => x.PictureIntentId)
-                .NotEmpty();
+                .NotEqual(Guid.Empty)
+                .When(x => x.PictureIntentId.HasValue);
 
             RuleFor(x => x.AudioIntentId)
                 .NotEmpty();

backend/Hosts/Musify.Api/Validators/Tracks/RequestTrackUploadUrlsRequestValidator.cs

@@ -6,25 +6,53 @@ namespace Musify.Api.Validators.Tracks
 {
     public sealed class RequestTrackUploadUrlsRequestValidator : AbstractValidator<RequestTrackUploadUrlsRequest>
     {
+        public const int MaxAudiosPerRequest = 20;
+
         public RequestTrackUploadUrlsRequestValidator(UploadIntentConfiguration uploadConfiguration)
         {
-            RuleFor(x => x.PictureFileType)
-                .MustBeFileType(Uploads.PictureFileTypes);
+            When(x => x.PictureFileType != null || x.PictureContentType != null, () =>
+            {
+                RuleFor(x => x.PictureFileType!)
+                    .MustBeFileType(Uploads.PictureFileTypes);
 
-            RuleFor(x => x.PictureContentType)
-                .MustBeContentType(Uploads.PictureContentTypes);
+                RuleFor(x => x.PictureContentType!)
+                    .MustBeContentType(Uploads.PictureContentTypes);
 
-            RuleFor(x => x.AudioFileType)
-                .MustBeFileType(Uploads.AudioFileTypes);
+                RuleFor(x => x.ExpectedPictureSizeBytes)
+                    .MustBeValidUploadSize(uploadConfiguration.MaxUploadBytes);
+            });
 
-            RuleFor(x => x.AudioContentType)
-                .MustBeContentType(Uploads.AudioContentTypes);
+            When(x => x.Audios is { Count: > 0 }, () =>
+            {
+                RuleFor(x => x.AudioFileType)
+                    .Null()
+                    .WithMessage("Use either the audio fields or the audios list, not both.");
 
-            RuleFor(x => x.ExpectedPictureSizeBytes)
-                .MustBeValidUploadSize(uploadConfiguration.MaxUploadBytes);
+                RuleFor(x => x.AudioContentType)
+                    .Null()
+                    .WithMessage("Use either the audio fields or the audios list, not both.");
 
-            RuleFor(x => x.ExpectedAudioSizeBytes)
-                .MustBeValidUploadSize(uploadConfiguration.MaxUploadBytes);
+                RuleFor(x => x.Audios!)
+                    .Must(audios => audios.Count <= MaxAudiosPerRequest)
+                    .WithMessage($"At most {MaxAudiosPerRequest} audio files can be requested at once.");
+
+                RuleForEach(x => x.Audios!).ChildRules(audio =>
+                {
+                    audio.RuleFor(a => a.FileType).MustBeFileType(Uploads.AudioFileTypes);
+                    audio.RuleFor(a => a.ContentType).MustBeContentType(Uploads.AudioContentTypes);
+                    audio.RuleFor(a => a.ExpectedSizeBytes).MustBeValidUploadSize(uploadConfiguration.MaxUploadBytes);
+                });
+            }).Otherwise(() =>
+            {
+                RuleFor(x => x.AudioFileType!)
+                    .MustBeFileType(Uploads.AudioFileTypes);
+
+                RuleFor(x => x.AudioContentType!)
+                    .MustBeContentType(Uploads.AudioContentTypes);
+
+                RuleFor(x => x.ExpectedAudioSizeBytes)
+                    .MustBeValidUploadSize(uploadConfiguration.MaxUploadBytes);
+            });
         }
     }
 }

backend/Hosts/Musify.Api/Validators/Tracks/SetTracksPublishedRequestValidator.cs

@@ -0,0 +1,21 @@
+using FluentValidation;
+using Musify.Api.DataTransferObjects.Tracks;
+
+namespace Musify.Api.Validators.Tracks
+{
+    public sealed class SetTracksPublishedRequestValidator : AbstractValidator<SetTracksPublishedRequest>
+    {
+        public const int MaxTracksPerRequest = 100;
+
+        public SetTracksPublishedRequestValidator()
+        {
+            RuleFor(x => x.TrackIds)
+                .NotEmpty()
+                .Must(ids => ids.Count <= MaxTracksPerRequest)
+                .WithMessage($"At most {MaxTracksPerRequest} tracks can be updated at once.");
+
+            RuleForEach(x => x.TrackIds)
+                .NotEmpty();
+        }
+    }
+}