feat: link transit registration to boxing

test/services/registration_linking_test.dart

@@ -0,0 +1,85 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pad_scanner/services/code_parser.dart';
+import 'package:pad_scanner/services/registration_linking.dart';
+
+void main() {
+  group('registration linking helpers', () {
+    test('detects transit target by type or code prefix', () {
+      expect(isTransitTarget(CodeType.locationTransit, 'TRANS-01'), isTrue);
+      expect(isTransitTarget(CodeType.locationNormal, 'TRANS-02'), isTrue);
+      expect(isTransitTarget(CodeType.locationNormal, 'A01-02-03'), isFalse);
+      expect(isTransitTarget(null, null), isFalse);
+    });
+
+    test('builds submit labels for normal and transit modes', () {
+      expect(
+        registrationSubmitLabel(
+          isTransitTarget: false,
+          isLocked: false,
+          zongpaiCount: 1,
+        ),
+        '确 认 上 架',
+      );
+      expect(
+        registrationSubmitLabel(
+          isTransitTarget: false,
+          isLocked: true,
+          zongpaiCount: 3,
+        ),
+        '批量上架（3 条）',
+      );
+      expect(
+        registrationSubmitLabel(
+          isTransitTarget: true,
+          isLocked: false,
+          zongpaiCount: 1,
+        ),
+        '转运并装箱',
+      );
+      expect(
+        registrationSubmitLabel(
+          isTransitTarget: true,
+          isLocked: true,
+          zongpaiCount: 3,
+        ),
+        '批量转运并凑箱（3 条）',
+      );
+    });
+
+    test('uses orange submit color only for enabled transit target', () {
+      const primary = Colors.blue;
+      expect(
+        registrationSubmitColor(
+          canSubmit: true,
+          isTransitTarget: true,
+          primaryColor: primary,
+        ),
+        Colors.orange,
+      );
+      expect(
+        registrationSubmitColor(
+          canSubmit: true,
+          isTransitTarget: false,
+          primaryColor: primary,
+        ),
+        primary,
+      );
+      expect(
+        registrationSubmitColor(
+          canSubmit: false,
+          isTransitTarget: true,
+          primaryColor: primary,
+        ),
+        Colors.grey.shade300,
+      );
+    });
+
+    test('validates all codes belong to one paicha', () {
+      expect(allSamePaicha(['R00001', 'R00001']), isTrue);
+      expect(allSamePaicha(['R00001', 'R00002']), isFalse);
+      expect(allSamePaicha(['R00001', null]), isFalse);
+      expect(allSamePaicha(<String>[]), isFalse);
+    });
+  });
+}