feat(app): the path editor in two cards, as before

On the tinted ground, one card holds the path's details (title,
secondary title, a line, the description row, a line, its tags behind an
Add tags chip) and one below holds its steps under their header, lines
between them, filling the window at least.

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

@@ -368,6 +368,9 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get pathTags => 'Tags';
 
+  @override
+  String get pathEditTags => 'Tags bearbeiten';
+
   @override
   String get pathSteps => 'Schritte';