feat(app): a note as one card, as before

A note is one card on the tinted ground: its title, its tags behind an
Add tags chip, a line, then its text. The app bar says only how saving
stands; its "Note in …" title goes.

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/src/app/app_router.dart

@@ -282,11 +282,11 @@ Widget _noteEditor(BuildContext context, String studysetId, {String? noteId}) {
     id: studysetId,
     items: person.studysets.watchAll,
     idOf: (studyset) => studyset.id,
-    builder: (studyset, _) => BlocProvider(
+    builder: (_, _) => BlocProvider(
       create: (context) =>
           NoteEditorBloc(person.notes, person.tags, studysetId, noteId: noteId)
             ..add(const NoteEditorEventStarted()),
-      child: NoteEditorScreen(studysetTitle: studyset.content.title),
+      child: const NoteEditorScreen(),
     ),
   );
 }