feat(app): kanji and kana in the dictionary, beside the words

Where the instance holds the characters of a studyset's language, the
dictionary screen has a tab for them, Kanji & kana: search by character,
reading (kana or romaji) or meaning, and whole levels to add, under their
names: the kana (hiragana, katakana), the JLPT levels and the school
grades. A character becomes a character card, its meanings (a kana's
romaji) and readings, tagged with its level (JLPT-N5), school grade
(Grade 1 … Grade 6, Secondary school) and script (Hiragana, Katakana). A
character card's Look up searches the characters, and an entry looked up
again on a card swaps the tags the one before brought, as words do.

A dictionary's entries are now words or characters (DictionaryItem), as
its kind says.

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/test/feature/dictionary/dictionary_screen_test.dart

@@ -2,6 +2,7 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:halkyon_learn_flutter/src/core/content/rich_content.dart';
 import 'package:halkyon_learn_flutter/src/core/router/route_paths.dart';
 import 'package:halkyon_learn_flutter/src/feature/card/data/card_repository.dart';
+import 'package:halkyon_learn_flutter/src/feature/card/model/card_content.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/data/studyset_payload.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/model/studyset_content.dart';
 import 'package:material_ui/material_ui.dart';
@@ -36,6 +37,23 @@ final toukyou = word(
   pos: ['n'],
 );
 
+final shoku = character(
+  '食',
+  meanings: ['eat', 'food'],
+  on: ['ショク'],
+  kun: ['た.べる'],
+  labels: ['jlpt:n5', 'grade:2'],
+  grade: 2,
+  strokes: 9,
+);
+final a = character('あ', labels: ['hiragana'], romaji: 'a');
+
+/// An instance with JMdict and KANJIDIC2.
+FakeDictionaryGateway withKanji() => FakeDictionaryGateway(
+  available: [jmdict, kanjidic],
+  words: [taberu, terebi, shoku, a],
+);
+
 void main() {
   late FakeCardGateway cardGateway;
   late CardRepository cards;
@@ -203,6 +221,72 @@ void main() {
     );
   });
 
+  testWidgets('beside the words, kanji and kana: their levels in groups, '
+      'one added as character cards tagged with level and grade', (
+    tester,
+  ) async {
+    await show(tester, dictionaries: withKanji());
+    await addMaterial(tester, 'From the dictionary');
+
+    expect(find.text('Words'), findsOneWidget);
+    await tester.tap(find.text('Kanji & kana'));
+    await settle(tester);
+    expect(find.text('Kana'), findsOneWidget);
+    expect(find.text('JLPT levels'), findsOneWidget);
+    expect(find.text('School grades'), findsOneWidget);
+    expect(find.text('Grade 2'), findsOneWidget);
+    await tester.tap(find.text('N5').hitTestable());
+    await tester.pumpAndSettle();
+    await tester.tap(find.text('Add 1 character'));
+    await tester.pumpAndSettle();
+
+    expect(find.text('Added 1 character.'), findsOneWidget);
+    final made = (await cards.cardsOf('japanese')).single;
+    expect(made.content.type, CardType.character);
+    expect(made.content.onReadings, ['ショク']);
+    expect(made.content.entry, (source: 'kanjidic', id: '食'));
+  });
+
+  testWidgets('a character found shows its readings and strokes, and is '
+      'added as a card', (tester) async {
+    await show(tester, dictionaries: withKanji());
+    await addMaterial(tester, 'From the dictionary');
+    await tester.tap(find.text('Kanji & kana'));
+    await settle(tester);
+
+    await tester.enterText(find.byType(TextField).hitTestable(), 'ショク');
+    await tester.pump(const Duration(milliseconds: 300));
+    await tester.pumpAndSettle();
+    expect(find.text('ショク · た.べる'), findsOneWidget);
+    expect(find.text('9 strokes'), findsOneWidget);
+    await tester.tap(find.text('Add').hitTestable());
+    await tester.pumpAndSettle();
+
+    expect(find.text('Added “食”.'), findsOneWidget);
+  });
+
+  testWidgets('Look up fills a character card with its meanings, readings '
+      'and tags', (tester) async {
+    await show(tester, dictionaries: withKanji());
+    await addMaterial(tester, 'Create flashcards');
+    await tester.tap(find.text('Character'));
+    await settle(tester);
+
+    await tester.tap(find.byTooltip('Look up in the dictionary'));
+    await tester.pumpAndSettle();
+    await tester.enterText(find.byType(TextField).last, 'eat');
+    await tester.pump(const Duration(milliseconds: 300));
+    await tester.pumpAndSettle();
+    await tester.tap(find.text('eat; food'));
+    await settle(tester);
+
+    expect(find.widgetWithText(TextField, 'eat'), findsOneWidget);
+    expect(find.widgetWithText(TextField, 'ショク'), findsOneWidget);
+    expect(find.widgetWithText(TextField, 'た.べる'), findsOneWidget);
+    expect(find.text('JLPT-N5'), findsOneWidget);
+    expect(find.text('Grade 2'), findsOneWidget);
+  });
+
   testWidgets('Look up fills a vocabulary card with a word of the '
       'dictionary', (tester) async {
     await show(tester);