fix: ktv_adapter pipeline_service导入改为可选

app/ktv_adapter.py

@@ -809,8 +809,11 @@ KTV_HANDLERS = {
 
 
 def load_ktv_adapter():
+    try:
         from pipeline_service.handler import register_handler
         for step_type, fn in KTV_HANDLERS.items():
             register_handler(step_type, fn)
         logger.info(f"Registered {len(KTV_HANDLERS)} KTV handlers (via llmage API, "
                     f"base={API_BASE})")
+    except ImportError:
+        logger.warning("pipeline_service not available, KTV handlers not registered")