feat(publish): the Publish sheet lists the tag names a release sends (ADR 0019)

Before Publish, the sheet shows the names of the tags that go with the
release, which the instance learns, sorted, or that none go; none where
they can't be had, as something in the tree is private (the short
reading of 22 Oct, finding 5). In English and German.

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

apps/learn/halkyon_learn_flutter/test/feature/publish/widget/publish_tag_names_test.dart

@@ -0,0 +1,42 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:halkyon_learn_flutter/src/core/l10n/app_languages.dart';
+import 'package:halkyon_learn_flutter/src/feature/publish/widget/publish_sheet.dart';
+import 'package:material_ui/material_ui.dart';
+
+/// The Publish sheet shows the names of the tags a release sends before
+/// Publish, as the instance learns each (ADR 0019, the short reading of 22
+/// Oct).
+void main() {
+  Future<void> pump(
+    WidgetTester tester,
+    Future<Map<String, String>> names,
+  ) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        localizationsDelegates: appLocalizationsDelegates,
+        home: Scaffold(body: PublishTagNames(names: names)),
+      ),
+    );
+    await tester.pump();
+  }
+
+  testWidgets('lists every name sent, sorted', (tester) async {
+    await pump(tester, Future.value({'t2': 'Verbs', 't1': 'JLPT-N3'}));
+
+    expect(find.textContaining('JLPT-N3, Verbs'), findsOneWidget);
+  });
+
+  testWidgets('says when none go with it', (tester) async {
+    await pump(tester, Future.value(const {}));
+
+    expect(find.text('No tags go with it.'), findsOneWidget);
+  });
+
+  testWidgets('shows no name where they can not be had (something private)', (
+    tester,
+  ) async {
+    await pump(tester, Future(() => throw StateError('private')));
+
+    expect(find.textContaining('JLPT'), findsNothing);
+  });
+}