feat: add Flutter mobile clients and staff delivery API

apps/service_app/test/domain/service_models_test.dart

@@ -0,0 +1,31 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:service_app/domain/models/service_models.dart';
+
+void main() {
+  group('WorkItem', () {
+    test('maps delivery allowed actions from server', () {
+      final item = WorkItem.delivery({
+        'identity': 'order-1',
+        'order_no': 'GAS001',
+        'order_status': 33,
+        'allowed_actions': ['append_tracks', 'arrive', 'exception'],
+      });
+
+      expect(item.identity, 'order-1');
+      expect(item.allowedActions, contains('arrive'));
+      expect(statusName(item.status), '配送中');
+    });
+
+    test('derives ticket actions from server status', () {
+      final item = WorkItem.ticket({
+        'identity': 'ticket-1',
+        'ticket_no': 'TK001',
+        'ticket_status': 11,
+        'category': 'inspection',
+      });
+
+      expect(item.title, '安全检查');
+      expect(item.allowedActions, contains('submit_result'));
+    });
+  });
+}