迁移 Flutter 端与训练脚本，模型/训练产物移出 git（遵循纯代码约定）

flutter_app/lib/auth/session_store.dart

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+import 'package:flutter_secure_storage/flutter_secure_storage.dart';
+
+/// 登录会话持久化：token + 手机号存 secure storage。
+/// 启动时读取判断是否已登录；登出/401 时清除回登录页。
+class SessionStore {
+  static const _storage = FlutterSecureStorage();
+  static const _tokenKey = 'auth_token';
+  static const _phoneKey = 'auth_phone';
+
+  static String? _cachedToken;
+  static String? _cachedPhone;
+
+  Future<String?> readToken() async {
+    if (_cachedToken != null) return _cachedToken;
+    return _cachedToken = await _storage.read(key: _tokenKey);
+  }
+
+  Future<String?> readPhone() async {
+    if (_cachedPhone != null) return _cachedPhone;
+    return _cachedPhone = await _storage.read(key: _phoneKey);
+  }
+
+  Future<void> save(String phone, String token) async {
+    _cachedPhone = phone;
+    _cachedToken = token;
+    await _storage.write(key: _phoneKey, value: phone);
+    await _storage.write(key: _tokenKey, value: token);
+  }
+
+  Future<void> clear() async {
+    _cachedPhone = null;
+    _cachedToken = null;
+    await _storage.delete(key: _phoneKey);
+    await _storage.delete(key: _tokenKey);
+  }
+}