refactor(observability): Phase2.2 成本归因 trace_id列+token日志写入+LLM/MCP/媒体子span [v2026.07.19.3]

backend/python/app/middleware/log_service.py

@@ -57,7 +57,7 @@ class LogService:
                         app_id: str = None, app_name: str = None,
                         conversation_id: str = None, prompt_tokens: int = 0,
                         completion_tokens: int = 0, total_tokens: int = 0,
-                        cost: float = 0):
+                        cost: float = 0, trace_id: str = None):
         """记录Token消耗日志"""
         db = SessionLocal()
         try:
@@ -73,6 +73,7 @@ class LogService:
                 completion_tokens=completion_tokens,
                 total_tokens=total_tokens,
                 cost=cost,
+                trace_id=trace_id,
             )
             db.add(log)
             db.commit()