Clean up Application layer commands/queries readability and correctness

Add missing AsNoTracking() on read-only queries, drop redundant
Update() calls on already-tracked entities, and fix inconsistent
formatting (stray spaces in generics, ternaries, and lambdas) across
the Albums/Tracks/PlayLists/Users command and query handlers.

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

@@ -14,6 +14,7 @@ namespace Musify.Application.Tracks
         public async ValueTask<ErrorOr<TrackApplicationResponse>> Handle(GetLastTrackListenedByUserIdQuery query, CancellationToken cancellationToken)
         {
             var track = await database.ListeningHistories
+                .AsNoTracking()
                 .Include(t => t.Track.Owner)
                 .Include(t => t.Track.Tags)
                 .Where(t => t.UserId == query.UserId)

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

@@ -16,6 +16,7 @@ namespace Musify.Application.Tracks
         public async ValueTask<IEnumerable<TrackApplicationResponse>> Handle(GetListeningHistoryQuery query, CancellationToken cancellationToken)
         {
             var recentTrackIds = await database.ListeningHistories
+                .AsNoTracking()
                 .Where(l => l.UserId == query.UserId)
                 .GroupBy(l => l.TrackId)
                 .OrderByDescending(g => g.Max(l => l.ListenedAt))
@@ -24,14 +25,15 @@ namespace Musify.Application.Tracks
                 .ToListAsync(cancellationToken);
 
             var tracksById = await database.Tracks
+                .AsNoTracking()
                 .Include(t => t.Owner)
                 .Include(t => t.Tags)
                 .Where(t => recentTrackIds.Contains(t.Id))
-                .Select(t => new { t.Id, Track = t, ListensCount = t.ListeningHistories.Count } )
+                .Select(t => new { t.Id, Track = t, ListensCount = t.ListeningHistories.Count })
                 .ToDictionaryAsync(t => t.Id, cancellationToken);
 
             return recentTrackIds
-                .Select(id => tracksById[id] )
+                .Select(id => tracksById[id])
                 .Select(t => TrackApplicationResponse.FromEntity(t.Track, t.ListensCount));
         }
     }

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

@@ -10,7 +10,7 @@ namespace Musify.Application.Tracks
         : IQuery<ErrorOr<TrackApplicationResponse>>;
 
     public class GetTrackByIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetTrackByIdQuery, ErrorOr<TrackApplicationResponse> >
+        : IQueryHandler<GetTrackByIdQuery, ErrorOr<TrackApplicationResponse>>
     {
         public async ValueTask<ErrorOr<TrackApplicationResponse>> Handle(GetTrackByIdQuery request, CancellationToken cancellationToken)
         {

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

@@ -48,6 +48,6 @@ namespace Musify.Application.Tracks
         }
 
         private static string? BuildKey(Func<string, string> builder, string? name)
-            => string.IsNullOrEmpty(name)? null: builder(name);
+            => string.IsNullOrEmpty(name) ? null : builder(name);
     }
 }

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

@@ -33,7 +33,7 @@ namespace Musify.Application.Tracks
             var pagedEntities = await tracksQuery
                 .OrderByDescending(t => t.Track.CreatedAt)
                 .ThenBy(t => t.Id)
-                .Select(t => new { t.Track, ListensCount = t.Track.ListeningHistories.Count } )
+                .Select(t => new { t.Track, ListensCount = t.Track.ListeningHistories.Count })
                 .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
 
             var items = pagedEntities

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

@@ -14,12 +14,12 @@ namespace Musify.Application.Tracks
         string? Name,
         int PageNumber,
         int PageSize)
-        : IQuery<ErrorOr<PaginatedResponse<TrackApplicationResponse> > >;
+        : IQuery<ErrorOr<PaginatedResponse<TrackApplicationResponse>>>;
 
     public class GetTracksByUserIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetTracksByUserIdQuery, ErrorOr<PaginatedResponse<TrackApplicationResponse>> >
+        : IQueryHandler<GetTracksByUserIdQuery, ErrorOr<PaginatedResponse<TrackApplicationResponse>>>
     {
-        public async ValueTask<ErrorOr<PaginatedResponse<TrackApplicationResponse> >> Handle(GetTracksByUserIdQuery request, CancellationToken cancellationToken)
+        public async ValueTask<ErrorOr<PaginatedResponse<TrackApplicationResponse>>> Handle(GetTracksByUserIdQuery request, CancellationToken cancellationToken)
         {
             var pageNumber = request.PageNumber < 1 ? 1 : request.PageNumber;
             var pageSize = request.PageSize < 1 ? 10 : request.PageSize;