fix(client): 自动连接门控改判生效节点就绪 + _connect 诊断日志(1.0.23)

自动连接已正确触发,但 _connect 撞 node.uuid.isEmpty 报「节点尚未就绪」:门控用的是
nodes.any(uuid),而 _connect 用 effectiveNode。改门控直接判 effectiveNode.uuid 非空(与
_connect 同一判据)。_connect 加一行日志记录 node/uuid/selected/nodes 便于确认。

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

client/lib/main.dart

@@ -135,14 +135,15 @@ class _RootFlowState extends ConsumerState<RootFlow> {
     void tryGo() {
       if (decided) return;
       final settings = ref.read(settingsProvider);
-      final nodes = ref.read(nodesProvider).valueOrNull ?? const <Node>[];
-      final nodesReady = nodes.any((n) => n.uuid.isNotEmpty);
-      if (!settings.loaded || !nodesReady) return; // 等两者都就绪
+      // 直接判 _connect 实际会用的「生效节点」是否就绪(uuid 非空),而非「列表里有任一就绪节点」——
+      // 否则可能在 effectiveNode 尚是占位/未就绪时就触发,_connect 报「节点尚未就绪」。
+      final node = ref.read(effectiveNodeProvider);
+      if (!settings.loaded || node.uuid.isEmpty) return;
       decided = true;
       nodeSub?.close();
       settingsSub?.close();
       final phase = ref.read(connectionProvider).phase;
-      logLine('AutoConnect', 'ready: autoConnect=${settings.autoConnect} phase=$phase nodes=${nodes.length}');
+      logLine('AutoConnect', 'ready: autoConnect=${settings.autoConnect} phase=$phase node=${node.code} uuid=${node.uuid.isEmpty ? "EMPTY" : "ok"}');
       if (settings.autoConnect && phase == VpnPhase.off) {
         logLine('AutoConnect', 'triggering connect');
         ref.read(connectionProvider.notifier).toggle();