feat: add Flutter mobile clients and staff delivery API

apps/user_app/lib/domain/models/client_models.dart

@@ -0,0 +1,50 @@
+class ClientRecord {
+  const ClientRecord({
+    required this.identity,
+    required this.title,
+    required this.subtitle,
+    required this.raw,
+    this.status,
+  });
+
+  final String identity;
+  final String title;
+  final String subtitle;
+  final int? status;
+  final Map<String, Object?> raw;
+}
+
+class UserProfile {
+  const UserProfile({
+    required this.identity,
+    required this.name,
+    required this.phone,
+    required this.avatar,
+  });
+
+  final String identity;
+  final String name;
+  final String phone;
+  final String avatar;
+
+  factory UserProfile.fromJson(Map<String, Object?> json) => UserProfile(
+    identity: json['identity'] as String? ?? '',
+    name: json['name'] as String? ?? '',
+    phone: json['phone'] as String? ?? '',
+    avatar: json['avatar'] as String? ?? '',
+  );
+}
+
+class WalletSummary {
+  const WalletSummary({required this.balance, required this.withdrawalBalance});
+
+  final int balance;
+  final int withdrawalBalance;
+
+  factory WalletSummary.fromJson(Map<String, Object?> json) => WalletSummary(
+    balance: (json['balance'] as num?)?.toInt() ?? 0,
+    withdrawalBalance: (json['withdrawal_balance'] as num?)?.toInt() ?? 0,
+  );
+}
+
+String moneyText(int cents) => '¥${(cents / 100).toStringAsFixed(2)}';