perf: recover lost files (locale_selector.dart, terminology.py, app_zh_hant.arb)

These files were accidentally omitted during cherry-pick workflow.
They were present in 639ef12 but dropped when switching to git apply workflow.

apps/lib/shared/utils/locale_selector.dart

@@ -0,0 +1,34 @@
+import 'package:flutter/material.dart';
+
+/// Locale-aware name selector for terminology fields.
+///
+/// Selects the appropriate field based on user locale:
+/// - zh-Hant (Traditional Chinese) → uses `_hant` suffix fields
+/// - zh (Simplified Chinese) or en (English) → uses base fields
+class LocaleNameSelector {
+  const LocaleNameSelector._(this._isHant);
+
+  final bool _isHant;
+
+  /// Creates a selector from the given [locale].
+  factory LocaleNameSelector.fromLocale(Locale locale) {
+    final isHant = locale.scriptCode == 'Hant';
+    return LocaleNameSelector._(isHant);
+  }
+
+  /// Creates a selector from the given [context].
+  factory LocaleNameSelector.of(BuildContext context) {
+    final locale = Localizations.localeOf(context);
+    return LocaleNameSelector.fromLocale(locale);
+  }
+
+  /// Selects between simplified and traditional Chinese name.
+  ///
+  /// Returns [nameHant] for zh-Hant locale, [name] otherwise.
+  String name(String name, String nameHant) {
+    return _isHant ? nameHant : name;
+  }
+
+  /// Returns true if the current locale uses Traditional Chinese.
+  bool get isTraditionalChinese => _isHant;
+}