feat: improve scan UX — case normalization, lock-mode list, layout swap

- CodeParser: normalize scanned barcode to uppercase and trim whitespace
  to handle scanner hardware outputting lowercase or trailing characters
- RegistrationPage: swap layout so location field is above zongpai field
- Lock mode: zongpai display changes to scrollable list supporting
  multiple entries with swipe-to-delete and per-item delete buttons
- Lock mode: batch submit when multiple zongpai numbers are queued
- Show scanned barcode content in invalid code error messages

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

test/services/code_parser_test.dart

@@ -39,8 +39,15 @@ void main() {
       final result = CodeParser.parse('TRANS-01');
       expect(result.type, CodeType.locationTransit);
     });
-    test('rejects lowercase location code', () {
-      expect(CodeParser.parse('a01-02-03').type, CodeType.invalid);
+    test('normalizes lowercase zongpaiNo to uppercase', () {
+      final result = CodeParser.parse('26b1');
+      expect(result.type, CodeType.zongpaiNo);
+      expect(result.value, '26B1');
+    });
+    test('normalizes lowercase location code to uppercase', () {
+      final result = CodeParser.parse('a01-02-03');
+      expect(result.type, CodeType.locationNormal);
+      expect(result.value, 'A01-02-03');
     });
     test('rejects invalid code', () {
       expect(CodeParser.parse('HELLO123').type, CodeType.invalid);