feat: Semantische Suche über Chat-History (memory_search)

- Lokales Embedding-Model (all-MiniLM-L6-v2, ONNX, CPU)
- EmbeddingService: WordPiece-Tokenizer + Mean Pooling (384 Dim)
- VectorSearchService: SQLite-basierte Vektor-Speicherung + Cosine Similarity
- EmbeddingBackgroundService: Backfill bestehender Messages + Live-Queue
- Neues Tool memory_search: Semantische Suche über alle Sessions (inkl. archivierte)
- ~9000 Messages embedded, Suche über komplette Chat-History

Program.cs

@@ -43,6 +43,15 @@ var reminderInterval = builder.Configuration.GetValue<int>("ReminderInterval", 3
 var chatService = new ChatService(dbService, toolService, memoryService, skillService, maxHistory, reminderInterval);
 builder.Services.AddSingleton(chatService);
 
+// Embedding-Services (lokal, ONNX)
+var embeddingService = new Gott.Services.EmbeddingService();
+builder.Services.AddSingleton(embeddingService);
+var vectorSearchService = new Gott.Services.VectorSearchService(dbPath, embeddingService);
+builder.Services.AddSingleton(vectorSearchService);
+var embeddingBgService = new Gott.Services.EmbeddingBackgroundService(vectorSearchService, embeddingService, dbPath);
+builder.Services.AddSingleton(embeddingBgService);
+builder.Services.AddHostedService(sp => sp.GetRequiredService<Gott.Services.EmbeddingBackgroundService>());
+
 // AnthropicService (Singleton – shared zwischen ChatEndpoint und TelegramService)
 var anthropicToken = builder.Configuration["AnthropicToken"] ?? "";
 var payloadLogging = builder.Configuration.GetValue<bool>("PayloadLogging", false);
@@ -51,7 +60,9 @@ builder.Services.AddSingleton<AnthropicService>(sp =>
     new AnthropicService(
         sp.GetRequiredService<IHttpClientFactory>(),
         anthropicToken, toolService, dbService, memoryService,
-        payloadLogging, payloadLoggingGzip));
+        payloadLogging, payloadLoggingGzip,
+        vectorSearch: vectorSearchService,
+        embeddingBg: embeddingBgService));
 
 // Telegram Bot (pro Session – Token aus Session-Config)
 var maxIterations = builder.Configuration.GetValue<int>("MaxIterations", 100);