feat: Chat-History auf max. 500 Nachrichten limitieren

Endpoints/HistoryEndpoint.cs

@@ -33,16 +33,31 @@ public static class HistoryEndpoint
             return;
         }
 
+        const int messageLimit = 500;
+
+        var totalCount = await db.GetActiveMessageCount(sessionId);
+        var messages = await db.GetLatestActiveMessages(sessionId, messageLimit);
+
+        // Nach Chain gruppieren (Reihenfolge beibehalten)
+        var chainIds = messages.Select(m => m.ChainId).Distinct().ToList();
         var chains = await db.GetActiveChains(sessionId);
+        var chainMap = chains.ToDictionary(c => c.ChainId);
 
         var result = new List<object>();
-        foreach (var chain in chains)
+        foreach (var chainId in chainIds)
         {
-            var messages = await db.GetChainMessages(chain.ChainId);
-            result.Add(new { chain, messages });
+            chainMap.TryGetValue(chainId, out var chain);
+            var chainMessages = messages.Where(m => m.ChainId == chainId).ToList();
+            result.Add(new { chain, messages = chainMessages });
         }
 
-        await ctx.Response.WriteAsJsonAsync(result);
+        await ctx.Response.WriteAsJsonAsync(new
+        {
+            entries = result,
+            hasMore = totalCount > messageLimit,
+            totalCount,
+            loadedCount = messages.Count
+        });
     }
 
     private static async Task HandlePoll(HttpContext ctx, DatabaseService db)