fix: use ValueKey<String> for reorderable grid and add status bar padding

flutter_reorderable_grid_view requires String keys, not int. Also
adds safe area top padding so the room grid doesn't overlap the
system status bar.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/l10n/app_localizations.dart

@@ -397,25 +397,25 @@ abstract class AppLocalizations {
   /// No description provided for @templatePickerTitle.
   ///
   /// In de, this message translates to:
-  /// **'Aufgaben aus Vorlagen hinzuf\u00fcgen?'**
+  /// **'Aufgaben aus Vorlagen hinzufügen?'**
   String get templatePickerTitle;
 
   /// No description provided for @templatePickerSkip.
   ///
   /// In de, this message translates to:
-  /// **'\u00dcberspringen'**
+  /// **'Überspringen'**
   String get templatePickerSkip;
 
   /// No description provided for @templatePickerAdd.
   ///
   /// In de, this message translates to:
-  /// **'Hinzuf\u00fcgen'**
+  /// **'Hinzufügen'**
   String get templatePickerAdd;
 
   /// No description provided for @templatePickerSelected.
   ///
   /// In de, this message translates to:
-  /// **'{count} ausgew\u00e4hlt'**
+  /// **'{count} ausgewählt'**
   String templatePickerSelected(int count);
 }