feat(dictionary): the radicals, each listing the kanji written with it

Beside Words and Kanji & kana, a Radicals tab lists the 214 Kangxi
radicals by their strokes, with the forms Japanese writes them as inside
kanji (亻, 氵, 艹, …). One chosen lists the kanji KANJIDIC2 files under
it, in the dictionary's order, to add or to see how one is written; the
tab shares the characters' bloc, so a kanji added there shows as held in
a search too.

The curator labels each kanji with its classical radical (`radical:N`),
so the server's existing label queries serve the tab unchanged. Its
files now say which conversion made them (`.conversion`): an instance
running a curator that converts differently converts again at once,
rather than at its weekly update, so the radicals appear right after a
deploy.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MMm7usAo6q9ZZRoPkWjoxi
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/lib/l10n/app_localizations_en.dart

@@ -2029,6 +2029,30 @@ class AppLocalizationsEn extends AppLocalizations {
     return '$_temp0';
   }
 
+  @override
+  String get dictionaryTabRadicals => 'Radicals';
+
+  @override
+  String get dictionaryRadicalsHint =>
+      'The 214 radicals that dictionaries order kanji by, grouped by their strokes. Choose one for the kanji written with it.';
+
+  @override
+  String get dictionaryAllRadicals => 'All radicals';
+
+  @override
+  String dictionaryRadicalNumber(int number) {
+    return 'Radical $number';
+  }
+
+  @override
+  String dictionaryRadicalKanjiCount(int count) {
+    return '$count kanji';
+  }
+
+  @override
+  String get dictionaryRadicalNone =>
+      'The instance\'s dictionary has no kanji under this radical yet.';
+
   @override
   String get dictionaryCharacterLevelsHint =>
       'Every character of a level becomes a flashcard, in the order of the level\'s list, tagged with its level, school grade or script. Characters already in this studyset are left out.';