fix(dictionary): a Greek letter found opens no empty sheet of strokes

Tapping a letter of the Greek alphabet among the dictionary's results
opened the character sheet, which could only say that there's no stroke
order for it. A letter of an alphabet has no strokes drawn, so the
dictionary now offers the tap only for characters of a script whose
strokes are drawn (Han characters, kana, Hangul), as a studied
character's answer does.

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

halkyon_learn_flutter/lib/src/feature/dictionary/widget/dictionary_screen.dart

@@ -15,6 +15,7 @@ import 'package:halkyon_learn_flutter/src/feature/dictionary/model/dictionary.da
 import 'package:halkyon_learn_flutter/src/feature/dictionary/widget/dictionary_lookup_sheet.dart';
 import 'package:halkyon_learn_flutter/src/feature/dictionary/widget/dictionary_word_tile.dart';
 import 'package:halkyon_learn_flutter/src/feature/dictionary/widget/studyset_dictionary.dart';
+import 'package:halkyon_learn_flutter/src/feature/kanji/model/hangul.dart';
 import 'package:halkyon_learn_flutter/src/feature/kanji/model/radical.dart';
 import 'package:halkyon_learn_flutter/src/feature/kanji/widget/character_sheet.dart';
 import 'package:lucide_icons_flutter/lucide_icons.dart';
@@ -311,7 +312,8 @@ class const _Results({required final DictionaryState state})
 }
 
 /// [items] to add, or marked as in the studyset; a character shows how it
-/// is written when tapped.
+/// is written when tapped, but for a letter of an alphabet (Greek's),
+/// which has no strokes drawn.
 class const _Items({
   required final List<DictionaryItem> items,
   required final DictionaryState state,
@@ -327,18 +329,21 @@ class const _Items({
         return dictionaryItemTile(
           word,
           onTap: switch (word) {
-            final DictionaryCharacter character => () => showCharacterSheet(
+            final DictionaryCharacter character
-              context,
+                when hasDrawnScript(character.headword) =>
-              character.headword,
+              () => showCharacterSheet(
-              facts: (
+                context,
-                meanings: character.meaningsShown,
+                character.headword,
-                onReadings: character.onReadings,
+                facts: (
-                kunReadings: character.kunReadings,
+                  meanings: character.meaningsShown,
-                marks: characterMarks(l10n, character),
+                  onReadings: character.onReadings,
+                  kunReadings: character.kunReadings,
+                  marks: characterMarks(l10n, character),
+                ),
+                language: character.language,
               ),
-              language: character.language,
+            // A letter of an alphabet (Greek's) has no strokes drawn.
-            ),
+            DictionaryCharacter() || DictionaryWord() => null,
-            DictionaryWord() => null,
           },
           trailing: state.inStudyset.contains(word.ref)
               ? Tooltip(

halkyon_learn_flutter/test/feature/dictionary/dictionary_screen_test.dart

@@ -394,6 +394,41 @@ void main() {
     expect(find.text('N5 · Grade 2'), findsOneWidget);
   });
 
+  testWidgets('a Greek letter found opens no sheet of its strokes: none are '
+      'drawn', (tester) async {
+    await show(
+      tester,
+      id: 'greek',
+      dictionaries: FakeDictionaryGateway(
+        available: [wiktionaryEl, greekAlphabet],
+        words: [
+          character(
+            'Α α',
+            labels: ['greek'],
+            romaji: 'a',
+            name: 'άλφα (alpha)',
+            of: greekAlphabet,
+          ),
+        ],
+      ),
+    );
+    await addMaterial(tester, 'From the dictionary');
+    await tester.tap(find.text('Alphabet'));
+    await settle(tester);
+    await tester.enterText(find.byType(TextField).hitTestable(), 'α');
+    await tester.pump(const Duration(milliseconds: 300));
+    await tester.pumpAndSettle();
+
+    await tester.tap(find.text('Α α').hitTestable());
+    await tester.pumpAndSettle();
+
+    expect(
+      find.text("There's no stroke order for this character."),
+      findsNothing,
+    );
+    expect(find.text('Play again'), findsNothing);
+  });
+
   testWidgets('Look up fills a character card with its meanings, readings '
       'and tags', (tester) async {
     await show(tester, dictionaries: withKanji());