refactor(observability): Phase2.1 统一可观测基座 trace_id+结构化日志+span计时 [v2026.07.19.2]

backend/python/main.py

@@ -25,6 +25,7 @@ from app.api.admin.developer_tools_admin import router as developer_tools_router
 from app.api.admin.mcp_market_admin import router as mcp_market_router
 from app.api.admin import asset_admin, achievement_admin
 from app.config import setup_file_logging, SLOW_REQUEST_THRESHOLD
+from app.core.observability import set_trace_id
 from app.database import SessionLocal
 from app.models import OperationLog as OperationLogModel, TokenUsageLog as TokenUsageLogModel
 
@@ -41,6 +42,7 @@ class APITrackingMiddleware(BaseHTTPMiddleware):
 
     async def dispatch(self, request: Request, call_next):
         request_id = str(uuid.uuid4())
+        set_trace_id(request_id)
         start_time = time.time()
         path = request.url.path
         method = request.method
@@ -53,6 +55,7 @@ class APITrackingMiddleware(BaseHTTPMiddleware):
             response = await call_next(request)
             elapsed = time.time() - start_time
             status_code = response.status_code
+            response.headers["X-Trace-Id"] = request_id
 
             if not should_skip:
                 access_logger.info(