feat: support box-number navigation for completed multi-code boxing & unify key handling

- In multi-code boxing mode, scanning a completed total-row number shows a
  clickable warning banner; clicking it or pressing P4 navigates to that
  box number to view boxing details.
- Unify key handling across all pages to LogicalKeyboardKey named constants,
  removing the _androidKeyCodeFromLogicalKey fallback path.

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

lib/pages/registration_page.dart

@@ -20,8 +20,6 @@ class RegistrationPage extends StatefulWidget {
 }
 
 class _RegistrationPageState extends State<RegistrationPage> {
-  static const _androidKeyCodeButtonR1 = 103;
-
   final _scannerService = ScannerService();
   final _apiService = ApiService();
   final _feedbackService = FeedbackService();
@@ -101,17 +99,7 @@ class _RegistrationPageState extends State<RegistrationPage> {
   bool _isLockToggleKey(KeyEvent event) {
     final key = event.logicalKey;
     return key == LogicalKeyboardKey.select ||
-        key == LogicalKeyboardKey.gameButtonRight1 ||
-        _androidKeyCodeFromLogicalKey(key) == _androidKeyCodeButtonR1;
-  }
-
-  int? _androidKeyCodeFromLogicalKey(LogicalKeyboardKey key) {
-    final keyId = key.keyId;
-    const androidPlane = LogicalKeyboardKey.androidPlane;
-    if (keyId >= androidPlane && keyId < androidPlane + 0x100000000) {
-      return keyId - androidPlane;
-    }
-    return null;
+        key == LogicalKeyboardKey.gameButtonRight1;
   }
 
   void _onScan(ScanResult result) {
@@ -676,13 +664,9 @@ class _RegistrationPageState extends State<RegistrationPage> {
             focusNode: dialogFocus,
             onKeyEvent: (event) {
               if (event is! KeyDownEvent) return;
-              final androidKey =
-                  _androidKeyCodeFromLogicalKey(event.logicalKey);
-              if (event.logicalKey == LogicalKeyboardKey.arrowUp ||
-                  androidKey == 19) {
+              if (event.logicalKey == LogicalKeyboardKey.arrowUp) {
                 setDialogState(() => selectedIndex = 0);
-              } else if (event.logicalKey == LogicalKeyboardKey.arrowDown ||
-                  androidKey == 20) {
+              } else if (event.logicalKey == LogicalKeyboardKey.arrowDown) {
                 setDialogState(() => selectedIndex = 1);
               } else if (event.logicalKey == LogicalKeyboardKey.enter) {
                 selectedIndex == 0 ? dismissAsNo() : confirmSwitch();