feat(registration): merge shelf overview into registration

test/services/api_service_test.dart

@@ -144,6 +144,86 @@ void main() {
   });
 
   group('ApiService boxing APIs', () {
+    test('fetchPaichaOverview parses overview items', () async {
+      final mockClient = _MockClient((request) async {
+        return http.Response(
+          jsonEncode({
+            'paicha_no': 'R00001',
+            'total_count': 2,
+            'items': [
+              {
+                'zongpai_no': '26B1',
+                'work_order_no': '6-1(7)',
+                'quantity': 80,
+                'location_code': 'A01-02-03',
+                'status': 'on_shelf',
+              },
+              {
+                'zongpai_no': '26B2',
+                'work_order_no': '6-2(3)',
+                'quantity': 45,
+                'location_code': null,
+                'status': 'not_shelved',
+              },
+            ],
+          }),
+          200,
+          headers: {'content-type': 'application/json; charset=utf-8'},
+        );
+      });
+
+      final svc = ApiService(client: mockClient);
+      final result = await svc.fetchPaichaOverview(
+        baseUrl: 'http://localhost',
+        zongpaiNo: '26B1',
+      );
+
+      expect(result.success, isTrue);
+      expect(result.paichaNo, 'R00001');
+      expect(result.totalCount, 2);
+      expect(result.items.first.status, 'on_shelf');
+      expect(result.items.last.locationCode, isNull);
+    });
+
+    test('fetchPaichaOverview maps 404 to not found result', () async {
+      final mockClient = _MockClient((request) async {
+        return http.Response(
+          jsonEncode({'error_code': 'PAICHA_NOT_FOUND', 'message': '暂无排产信息'}),
+          404,
+          headers: {'content-type': 'application/json; charset=utf-8'},
+        );
+      });
+
+      final svc = ApiService(client: mockClient);
+      final result = await svc.fetchPaichaOverview(
+        baseUrl: 'http://localhost',
+        zongpaiNo: '26B404',
+      );
+
+      expect(result.success, isFalse);
+      expect(result.notFound, isTrue);
+      expect(result.errorMessage, '暂无排产信息');
+    });
+
+    test(
+      'fetchPaichaOverview maps network failure to retryable error',
+      () async {
+        final mockClient = _MockClient((request) async {
+          throw Exception('Connection refused');
+        });
+
+        final svc = ApiService(client: mockClient);
+        final result = await svc.fetchPaichaOverview(
+          baseUrl: 'http://localhost',
+          zongpaiNo: '26B1',
+        );
+
+        expect(result.success, isFalse);
+        expect(result.notFound, isFalse);
+        expect(result.errorMessage, '加载失败，点击重试');
+      },
+    );
+
     test('fetchBoxInfo parses current boxes and box item ids', () async {
       final mockClient = _MockClient((request) async {
         return http.Response(