chore(client): 1.0.19 — 自动连接诊断日志

排查「自动连接没生效」:在 _RootFlow 自动连接路径(HomeShell 显示 / 节点就绪 / autoConnect/phase 判定 / 触发)
与 Settings(_load 读到的 autoConnect、setAutoConnect 落盘)加 logLine 日志,定位卡在哪一步。诊断完移除。

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

client/lib/state/settings_provider.dart

@@ -11,6 +11,7 @@ import 'package:launch_at_startup/launch_at_startup.dart';
 import 'package:package_info_plus/package_info_plus.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
+import '../bridge/log.dart';
 import '../bridge/vpn_bridge_provider.dart';
 
 class AppSettings {
@@ -59,6 +60,7 @@ class SettingsController extends StateNotifier<AppSettings> {
         smartRoute: p.getBool(_kSmartRoute) ?? true,
         killSwitch: p.getBool(_kKillSwitch) ?? true,
       );
+      logLine('Settings', 'loaded autoConnect=${state.autoConnect} autostart=${state.autostart}');
     } catch (_) {
       // 测试/无平台:保留默认值。
     }
@@ -76,6 +78,7 @@ class SettingsController extends StateNotifier<AppSettings> {
   Future<void> setAutoConnect(bool v) async {
     state = state.copyWith(autoConnect: v);
     await _persist(_kAutoConnect, v);
+    logLine('Settings', 'setAutoConnect=$v persisted');
   }
 
   Future<void> setSmartRoute(bool v) async {