Deck list work

SVSim.Database/Repositories/Deck/DeckRepository.cs

@@ -28,6 +28,27 @@ public class DeckRepository : IDeckRepository
                ?? new List<ShadowverseDeckEntry>();
     }
 
+    public async Task<Dictionary<Format, List<ShadowverseDeckEntry>>> GetDecksByFormats(long viewerId, IEnumerable<Format> formats)
+    {
+        var requested = formats.ToHashSet();
+        var viewer = await _dbContext.Viewers
+            .AsNoTracking()
+            .Include(v => v.Decks).ThenInclude(d => d.Class)
+            .Include(v => v.Decks).ThenInclude(d => d.Sleeve)
+            .Include(v => v.Decks).ThenInclude(d => d.LeaderSkin)
+            .FirstOrDefaultAsync(v => v.Id == viewerId);
+
+        // Seed every requested format with an empty list so callers iterate without null checks.
+        var result = requested.ToDictionary(f => f, _ => new List<ShadowverseDeckEntry>());
+        if (viewer is null) return result;
+
+        foreach (var deck in viewer.Decks.Where(d => requested.Contains(d.Format)).OrderBy(d => d.Number))
+        {
+            result[deck.Format].Add(deck);
+        }
+        return result;
+    }
+
     public async Task<ShadowverseDeckEntry?> GetDeck(long viewerId, Format format, int deckNo)
     {
         var viewer = await _dbContext.Viewers