diag(client): _onStats/setLivePing 打点,定位延迟为何不回写 node.ping

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/lib/state/nodes_provider.dart

@@ -14,6 +14,7 @@ import '../services/api_config.dart';
 import '../services/latency_probe.dart';
 import 'auth_provider.dart';
 import 'connection_provider.dart';
+import '../bridge/log.dart';
 
 // ── 节点列表 AsyncNotifier ────────────────────────────────────────
 
@@ -86,14 +87,24 @@ class NodesNotifier extends AsyncNotifier<List<Node>> {
   /// 回写某节点的实测延迟(ms)。连接态由 ConnectionController 用内核 urltest 回填连接节点,
   /// 让「连接页延迟」与「节点列表延迟」同源(都读 node.ping)、显示一致。ms<=0 忽略。
   void setLivePing(String uuid, int ms) {
-    if (ms <= 0 || _disposed) return;
+    if (ms <= 0 || _disposed) {
+      logLine('Ping', 'setLivePing SKIP ms=$ms disposed=$_disposed');
+      return;
+    }
     final list = state.valueOrNull;
-    if (list == null) return;
+    if (list == null) {
+      logLine('Ping', 'setLivePing no-list');
+      return;
+    }
     var changed = false;
     final updated = [
       for (final n in list)
         if (n.uuid == uuid && n.ping != ms) (() { changed = true; return n.copyWith(ping: ms); })() else n
     ];
+    final match = list.any((n) => n.uuid == uuid);
+    logLine('Ping',
+        'setLivePing ms=$ms match=$match changed=$changed '
+        'nodes=[${list.map((n) => "${n.code}:${n.ping}").join(",")}]');
     if (changed) state = AsyncData(updated);
   }