feat(todo): tasks chosen together, quick add reading what is typed (ADR 0033, D14, D15)

- A section's heading stays atop a project's list while its tasks
  scroll beneath it (slivers, PinnedHeaderSliver).
- Upcoming's month unfolds in place beneath its strip, from its name
  or its handle; a button beside the month goes back to today.
- Tasks are chosen together: a row swiped right or held, or Select
  tasks in Today's, Upcoming's and a project's menu; a bar of date,
  move, labels, priority and more (complete, duplicate, deadline,
  delete) takes the navigation bar's place. A row swiped left asks
  for its date.
- TaskRepository.move moves tasks with their sub-tasks.
- parseQuickAdd reads #project, @label (an unknown one made),
  {deadline}, !!1 and p1 to p4, !30m, dates, times and recurrences
  (tomorrow 9am, Mon 18:00, ev Tue 7pm, every 2 days, every weekday),
  from a table of words per language: English, and German beside it.
- Each token is highlighted and shown on its chip; a tap keeps it as
  text, and a chip picked takes it out of the title.
- Quick add shows its title alone at first, its chips once typing
  starts, and the description and deadline behind its + (the
  description also from the down arrow).

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/todo/halkyon_todo_flutter/lib/l10n/app_localizations.dart

@@ -939,6 +939,162 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Where the task is'**
   String get taskPath;
+
+  /// No description provided for @weekToday.
+  ///
+  /// In en, this message translates to:
+  /// **'Back to today'**
+  String get weekToday;
+
+  /// No description provided for @monthPrevious.
+  ///
+  /// In en, this message translates to:
+  /// **'Previous month'**
+  String get monthPrevious;
+
+  /// No description provided for @monthNext.
+  ///
+  /// In en, this message translates to:
+  /// **'Following month'**
+  String get monthNext;
+
+  /// No description provided for @monthShow.
+  ///
+  /// In en, this message translates to:
+  /// **'Show the whole month'**
+  String get monthShow;
+
+  /// No description provided for @monthHide.
+  ///
+  /// In en, this message translates to:
+  /// **'Show one week'**
+  String get monthHide;
+
+  /// No description provided for @selectTasks.
+  ///
+  /// In en, this message translates to:
+  /// **'Select tasks'**
+  String get selectTasks;
+
+  /// No description provided for @selectionCount.
+  ///
+  /// In en, this message translates to:
+  /// **'{count, plural, =0{Select tasks} =1{1 task selected} other{{count} tasks selected}}'**
+  String selectionCount(int count);
+
+  /// No description provided for @selectionEnd.
+  ///
+  /// In en, this message translates to:
+  /// **'Stop selecting'**
+  String get selectionEnd;
+
+  /// No description provided for @selectionDate.
+  ///
+  /// In en, this message translates to:
+  /// **'Date'**
+  String get selectionDate;
+
+  /// No description provided for @selectionMove.
+  ///
+  /// In en, this message translates to:
+  /// **'Move to'**
+  String get selectionMove;
+
+  /// No description provided for @selectionLabels.
+  ///
+  /// In en, this message translates to:
+  /// **'Labels'**
+  String get selectionLabels;
+
+  /// No description provided for @selectionPriority.
+  ///
+  /// In en, this message translates to:
+  /// **'Priority'**
+  String get selectionPriority;
+
+  /// No description provided for @selectionMore.
+  ///
+  /// In en, this message translates to:
+  /// **'More'**
+  String get selectionMore;
+
+  /// No description provided for @selectionDelete.
+  ///
+  /// In en, this message translates to:
+  /// **'{count, plural, =1{Delete 1 task} other{Delete {count} tasks}}'**
+  String selectionDelete(int count);
+
+  /// No description provided for @selectionDeleteTitle.
+  ///
+  /// In en, this message translates to:
+  /// **'Delete the tasks?'**
+  String get selectionDeleteTitle;
+
+  /// No description provided for @selectionDeleteMessage.
+  ///
+  /// In en, this message translates to:
+  /// **'{count, plural, =1{1 task is deleted with its sub-tasks, on all your devices.} other{{count} tasks are deleted with their sub-tasks, on all your devices.}}'**
+  String selectionDeleteMessage(int count);
+
+  /// No description provided for @selectionDuplicate.
+  ///
+  /// In en, this message translates to:
+  /// **'{count, plural, =1{Duplicate 1 task} other{Duplicate {count} tasks}}'**
+  String selectionDuplicate(int count);
+
+  /// No description provided for @selectionComplete.
+  ///
+  /// In en, this message translates to:
+  /// **'{count, plural, =1{Complete 1 task} other{Complete {count} tasks}}'**
+  String selectionComplete(int count);
+
+  /// No description provided for @selectionDeadline.
+  ///
+  /// In en, this message translates to:
+  /// **'Deadline'**
+  String get selectionDeadline;
+
+  /// No description provided for @tasksCompleted.
+  ///
+  /// In en, this message translates to:
+  /// **'{count, plural, =1{Task done} other{{count} tasks done}}'**
+  String tasksCompleted(int count);
+
+  /// No description provided for @swipeSelect.
+  ///
+  /// In en, this message translates to:
+  /// **'Select'**
+  String get swipeSelect;
+
+  /// No description provided for @swipeDate.
+  ///
+  /// In en, this message translates to:
+  /// **'Date'**
+  String get swipeDate;
+
+  /// No description provided for @tasksMenu.
+  ///
+  /// In en, this message translates to:
+  /// **'More'**
+  String get tasksMenu;
+
+  /// Quick add's + menu, holding Description and Deadline (ADR 0033, D15).
+  ///
+  /// In en, this message translates to:
+  /// **'More'**
+  String get quickAddMore;
+
+  /// Below quick add's title while it has tokens recognised (D15).
+  ///
+  /// In en, this message translates to:
+  /// **'Tap a highlighted word to keep it as text.'**
+  String get quickAddTokenHint;
+
+  /// Quick add's deadline chip and menu entry (D15).
+  ///
+  /// In en, this message translates to:
+  /// **'Deadline'**
+  String get deadlineTitle;
 }
 
 class _AppLocalizationsDelegate