修复：weblive 协程 panic 防护、Mongo 空指针防护、直播状态轮询退避

Made-with: Cursor

server/pkg/weblive/hub.go

@@ -154,7 +154,7 @@ func (h *Hub) onPublisherTrack(track *webrtc.TrackRemote) {
 	h.mu.Lock()
 	h.forwarders = append(h.forwarders, tf)
 	h.mu.Unlock()
-	go tf.runReadLoop()
+	goSafe("trackRead", tf.runReadLoop)
 	// 观众仅在「已开播」后拉流：首次协商时 attachForwardersToViewerPC 会带上当前全部轨，无需在此重协商
 }
 
@@ -173,14 +173,14 @@ func (h *Hub) attachForwardersToViewerPC(v *viewerSession) {
 			continue
 		}
 		// Drain RTCP feedback to keep interceptors/senders healthy.
-		go func() {
+		goSafe("viewerRTCP", func() {
 			rtcpBuf := make([]byte, 1500)
 			for {
 				if _, _, e := rtpSender.Read(rtcpBuf); e != nil {
 					return
 				}
 			}
-		}()
+		})
 		tf.addViewer(v.id, lt)
 	}
 }