feat(todo): dialogs on the desktop, the tabs reordered, a task's path and menu (ADR 0033, D11 to D14)

- halkyon_ui: showAdaptiveSheet shows a dialog on Linux, macOS and Windows
  at every width (bottom sheets stay on phones and tablets below expanded
  windows), so Learn and Train follow; SheetScaffold takes a heading in
  the title's place and may leave out its close button.
- Todo: the tabs are Inbox, Today, Upcoming, Browse, Today still opening;
  `serverpod start` launches the app on Linux, as it has no web build.
- A task's sheet shows where the task is (its project, an icon once tasks
  are above it, and the tasks above it, each opening what it names) and a
  ⋮ menu in place of its close button: when it was added (its UUID v7),
  Duplicate with its sub-tasks, hiding its done sub-tasks (synced in its
  payload), Close in the pane, Delete after asking. The description's icon
  stays by its first line.
- A row names its project and section at the end of its date's line; every
  menu entry has its icon.
- Learn: a studyset's path starts at the Library tab's icon, named by its
  tooltip.

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_de.arb

@@ -137,5 +137,13 @@
   "searchEmpty": "Finde eine Aufgabe über die Wörter in ihrem Titel, ihrer Beschreibung oder ihren Labels. Die Suche läuft auf diesem Gerät: deine Instanz kann deine Aufgaben nicht lesen.",
   "searchNone": "Nichts gefunden für „{query}“.",
   "searchProjects": "Projekte",
-  "searchTasks": "Aufgaben"
+  "searchTasks": "Aufgaben",
+  "taskMore": "Optionen der Aufgabe",
+  "taskAddedOn": "Hinzugefügt am {when}",
+  "taskDuplicate": "Duplizieren",
+  "taskDuplicated": "Aufgabe dupliziert",
+  "subTasksHideDone": "Erledigte Unteraufgaben ausblenden",
+  "subTasksShowDone": "Erledigte Unteraufgaben zeigen",
+  "taskClose": "Schließen",
+  "taskPath": "Wo die Aufgabe liegt"
 }

apps/todo/halkyon_todo_flutter/lib/l10n/app_en.arb

@@ -167,5 +167,14 @@
   "searchNone": "Nothing found for “{query}”.",
   "@searchNone": {"placeholders": {"query": {"type": "String"}}},
   "searchProjects": "Projects",
-  "searchTasks": "Tasks"
+  "searchTasks": "Tasks",
+  "taskMore": "Task options",
+  "taskAddedOn": "Added on {when}",
+  "@taskAddedOn": {"placeholders": {"when": {"type": "String"}}},
+  "taskDuplicate": "Duplicate",
+  "taskDuplicated": "Task duplicated",
+  "subTasksHideDone": "Hide done sub-tasks",
+  "subTasksShowDone": "Show done sub-tasks",
+  "taskClose": "Close",
+  "taskPath": "Where the task is"
 }

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

@@ -891,6 +891,54 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Tasks'**
   String get searchTasks;
+
+  /// No description provided for @taskMore.
+  ///
+  /// In en, this message translates to:
+  /// **'Task options'**
+  String get taskMore;
+
+  /// No description provided for @taskAddedOn.
+  ///
+  /// In en, this message translates to:
+  /// **'Added on {when}'**
+  String taskAddedOn(String when);
+
+  /// No description provided for @taskDuplicate.
+  ///
+  /// In en, this message translates to:
+  /// **'Duplicate'**
+  String get taskDuplicate;
+
+  /// No description provided for @taskDuplicated.
+  ///
+  /// In en, this message translates to:
+  /// **'Task duplicated'**
+  String get taskDuplicated;
+
+  /// No description provided for @subTasksHideDone.
+  ///
+  /// In en, this message translates to:
+  /// **'Hide done sub-tasks'**
+  String get subTasksHideDone;
+
+  /// No description provided for @subTasksShowDone.
+  ///
+  /// In en, this message translates to:
+  /// **'Show done sub-tasks'**
+  String get subTasksShowDone;
+
+  /// No description provided for @taskClose.
+  ///
+  /// In en, this message translates to:
+  /// **'Close'**
+  String get taskClose;
+
+  /// No description provided for @taskPath.
+  ///
+  /// In en, this message translates to:
+  /// **'Where the task is'**
+  String get taskPath;
 }
 
 class _AppLocalizationsDelegate

apps/todo/halkyon_todo_flutter/lib/l10n/app_localizations_de.dart

@@ -552,4 +552,30 @@ class AppLocalizationsDe extends AppLocalizations {
 
   @override
   String get searchTasks => 'Aufgaben';
+
+  @override
+  String get taskMore => 'Optionen der Aufgabe';
+
+  @override
+  String taskAddedOn(String when) {
+    return 'Hinzugefügt am $when';
+  }
+
+  @override
+  String get taskDuplicate => 'Duplizieren';
+
+  @override
+  String get taskDuplicated => 'Aufgabe dupliziert';
+
+  @override
+  String get subTasksHideDone => 'Erledigte Unteraufgaben ausblenden';
+
+  @override
+  String get subTasksShowDone => 'Erledigte Unteraufgaben zeigen';
+
+  @override
+  String get taskClose => 'Schließen';
+
+  @override
+  String get taskPath => 'Wo die Aufgabe liegt';
 }

apps/todo/halkyon_todo_flutter/lib/l10n/app_localizations_en.dart

@@ -552,6 +552,32 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get searchTasks => 'Tasks';
+
+  @override
+  String get taskMore => 'Task options';
+
+  @override
+  String taskAddedOn(String when) {
+    return 'Added on $when';
+  }
+
+  @override
+  String get taskDuplicate => 'Duplicate';
+
+  @override
+  String get taskDuplicated => 'Task duplicated';
+
+  @override
+  String get subTasksHideDone => 'Hide done sub-tasks';
+
+  @override
+  String get subTasksShowDone => 'Show done sub-tasks';
+
+  @override
+  String get taskClose => 'Close';
+
+  @override
+  String get taskPath => 'Where the task is';
 }
 
 /// The translations for English, as used in the United Kingdom (`en_GB`).