fix: include Release nav on all TrackRepository query paths; add unique constraint on release(title, artist)

DeepDrftData/Repositories/TrackRepository.cs

@@ -26,6 +26,16 @@ public class TrackRepository : Repository<DeepDrftContext, TrackEntity>
         _context = context;
     }
 
+    // Override base GetByIdAsync to include the Release navigation. Without this, the base
+    // Query has no .Include, so Release is null on every entity (no lazy-loading proxies).
+    public override async Task<TrackEntity?> GetByIdAsync(long id)
+        => await Query.Include(t => t.Release).FirstOrDefaultAsync(e => e.Id == id);
+
+    // Override base GetAllAsync for the same reason — include Release so callers (e.g.
+    // TrackManager.GetAll) receive fully-populated entities without a separate query.
+    public override async Task<IEnumerable<TrackEntity>> GetAllAsync()
+        => await Query.Include(t => t.Release).ToListAsync();
+
     // Lookup by vault entry key. The base Repository<> only exposes id-based queries, so this
     // uses Query (soft-delete filtered) rather than the raw DbSet. Includes Release so the
     // converter can project the release-cardinal fields.