refactor(app): remove unsupported runtime and UI state

lib/logic/connection_settings.dart

@@ -18,23 +18,32 @@ abstract final class ConnectionSettings {
     final prefs = await SharedPreferences.getInstance();
     final storedMode = prefs.getString(_modeKey);
 
-    // Any unrecognized value (including the pre-V3 'auto') is TUN. 'proxy' is
-    // the only persisted value that selects the SOCKS5 mode.
+    // Only the explicit current proxy value restores SOCKS5. Unknown and
+    // obsolete values, including the former 'auto'/'ass' labels, fail closed
+    // to full-tunnel TUN instead of silently selecting a weaker route.
     _mode = storedMode == ConnectionMode.proxy.name
         ? ConnectionMode.proxy
         : ConnectionMode.tun;
 
     if (storedMode != _mode.name) {
-      await prefs.setString(_modeKey, _mode.name);
+      final migrated = await prefs.setString(_modeKey, _mode.name);
+      if (!migrated) {
+        throw StateError('Could not persist migrated connection mode.');
+      }
     }
 
     _initialized = true;
   }
 
-  static Future<void> setMode(ConnectionMode mode) async {
+  static Future<bool> setMode(ConnectionMode mode) async {
+    if (_initialized && _mode == mode) return true;
+
+    final prefs = await SharedPreferences.getInstance();
+    final saved = await prefs.setString(_modeKey, mode.name);
+    if (!saved) return false;
+
     _mode = mode;
     _initialized = true;
-    final prefs = await SharedPreferences.getInstance();
-    await prefs.setString(_modeKey, mode.name);
+    return true;
   }
 }

lib/logic/power_settings.dart

@@ -1,13 +1,7 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
-/// Background-survival controls.
-///
-/// Android stops background services of apps that are not exempt from Doze and
-/// App Standby, and it tears down the whole process group when a task is swiped
-/// away. Those are OS behaviours, not app bugs; the battery-optimisation
-/// exemption is the one sanctioned way an app can ask for around them, and it
-/// still needs one user tap.
+/// Android background-survival controls that ReVolt can actually verify.
 abstract final class PowerSettings {
   PowerSettings._();
 
@@ -15,7 +9,6 @@ abstract final class PowerSettings {
     'com.revoltvpn.app/power',
   );
 
-  /// Whether the OS has exempted this app from Doze / App Standby.
   static Future<bool> isBatteryOptimisationDisabled() async {
     if (kIsWeb) return true;
     try {
@@ -28,8 +21,6 @@ abstract final class PowerSettings {
     }
   }
 
-  /// Shows the system exemption dialog. Returns false only when no system UI
-  /// could be opened at all — a user declining still returns true.
   static Future<bool> requestDisableBatteryOptimisation() async {
     if (kIsWeb) return true;
     try {
@@ -41,53 +32,4 @@ abstract final class PowerSettings {
       return false;
     }
   }
-
-  /// Whether the VPN runtime is genuinely alive.
-  ///
-  /// The Xray service runs in a separate process, so nothing it stores in
-  /// statics is visible to us. This asks the OS instead: is our service process
-  /// running, and (for TUN) is there an active VPN transport?
-  static Future<VpnRuntimeState> runtimeState() async {
-    if (kIsWeb) return const VpnRuntimeState(processAlive: false, vpnTransport: false);
-    try {
-      final result = await _channel.invokeMapMethod<String, dynamic>(
-        'isVpnRuntimeAlive',
-      );
-      return VpnRuntimeState(
-        processAlive: result?['processAlive'] == true,
-        vpnTransport: result?['vpnTransport'] == true,
-      );
-    } catch (_) {
-      return const VpnRuntimeState(processAlive: false, vpnTransport: false);
-    }
-  }
-
-  /// Pushes the absolute session-expiry timestamp (epoch ms) to the VPN
-  /// service so it can tear the tunnel down even when the UI process is gone.
-  static Future<void> setSessionExpiry(int expiresAtMs) async {
-    if (kIsWeb) return;
-    try {
-      await _channel.invokeMethod<void>('setSessionExpiry', {
-        'expiresAtMs': expiresAtMs,
-      });
-    } catch (_) {
-      // Best-effort. The daemon also keeps its last persisted expiry.
-    }
-  }
-}
-
-@immutable
-class VpnRuntimeState {
-  final bool processAlive;
-  final bool vpnTransport;
-
-  const VpnRuntimeState({
-    required this.processAlive,
-    required this.vpnTransport,
-  });
-
-  /// TUN needs both a live service and a real VPN interface. Proxy mode has no
-  /// VPN interface at all, so the service process is the whole signal.
-  bool aliveFor({required bool tunMode}) =>
-      processAlive && (!tunMode || vpnTransport);
 }

lib/logic/server_list.dart

@@ -1,69 +0,0 @@
-import 'package:flutter/foundation.dart';
-import 'package:shared_preferences/shared_preferences.dart';
-
-// ── lib/logic/server_list.dart ──────────────────────────────────────────────
-// Server data model and ChangeNotifier — shared by StatusBar (shows current
-// server name/flag) and SelectionScreen (lets user pick a server).
-//
-// Each server is defined by its tunnel IP/port. Reality credentials (public
-// key, shortId) come from /session/status per session; only the transport
-// parameters live in AppConfig.
-//
-// When multi-server ships:
-//   - _all becomes a fetched list (from /api/servers or bundled config)
-//   - SelectionScreen shows multiple rows
-//   - select() triggers a disconnect/reconnect cycle if the tunnel is active
-
-class ServerInfo {
-  final String id;
-  final String name;
-  final String flagAsset;
-  final String ip;
-  final int port;
-
-  const ServerInfo({
-    required this.id,
-    required this.name,
-    required this.flagAsset,
-    required this.ip,
-    required this.port,
-  });
-}
-
-class ServerList extends ChangeNotifier {
-  static const _all = [
-    ServerInfo(
-      id: 'finland',
-      name: 'Helsinki, Finland',
-      flagAsset: 'assets/finland_flag_256.png',
-      ip: '204.168.246.88',
-      port: 443,
-    ),
-  ];
-
-  int _selectedIndex = 0;
-
-  List<ServerInfo> get all => _all;
-  int get selectedIndex => _selectedIndex;
-  ServerInfo get selected => _all[_selectedIndex];
-
-  // Loads persisted selection from SharedPreferences.
-  // Fire-and-forget — UI starts with default, updates when prefs load.
-  Future<void> init() async {
-    final prefs = await SharedPreferences.getInstance();
-    final saved = prefs.getInt('selected_server_index') ?? 0;
-    if (saved >= 0 && saved < _all.length && saved != _selectedIndex) {
-      _selectedIndex = saved;
-      notifyListeners();
-    }
-  }
-
-  // Switches to a different server. Persists the choice.
-  Future<void> select(int index) async {
-    if (index == _selectedIndex || index < 0 || index >= _all.length) return;
-    _selectedIndex = index;
-    notifyListeners();
-    final prefs = await SharedPreferences.getInstance();
-    await prefs.setInt('selected_server_index', index);
-  }
-}