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/l10n/app_localizations_de.dart

@@ -775,16 +775,6 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get noteDeleted => 'Notiz gelöscht';
 
-  @override
-  String noteNewTitleFor(String title) {
-    return 'Neue Notiz in „$title“';
-  }
-
-  @override
-  String noteTitleFor(String title) {
-    return 'Notiz in „$title“';
-  }
-
   @override
   String get noteTitleHint => 'Titel';
 
@@ -817,7 +807,7 @@ class AppLocalizationsDe extends AppLocalizations {
   String get noteAddTags => 'Tags hinzufügen';
 
   @override
-  String get noteTags => 'Tags';
+  String get noteEditTags => 'Tags bearbeiten';
 
   @override
   String get studysetFlashcardsEmpty => 'Noch keine Karteikarten';