feat(todo): Today counts its tasks under its title

As Todoist's, Today's app bar says how many tasks it holds, those
overdue and those due today together ("3 tasks"). TabScreen takes an
optional subtitle for it, left out while tasks are being chosen, when
the title counts those instead.

Whats-New: Today says how many tasks are overdue or due today under its title.
Whats-New-De: „Heute“ zeigt unter dem Titel, wie viele Aufgaben überfällig oder heute fällig sind.

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

@@ -9,6 +9,7 @@
   "shellTabToday": "Heute",
   "shellTabUpcoming": "Demnächst",
   "shellTabInbox": "Eingang",
+  "todayCount": "{count, plural, =1{1 Aufgabe} other{{count} Aufgaben}}",
   "browseProfile": "Profil",
   "browseProfileHint": "Dein Konto, wie du dich anmeldest, und dein öffentliches Profil",
   "shellTabBrowse": "Übersicht",

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

@@ -15,6 +15,15 @@
   "shellTabToday": "Today",
   "shellTabUpcoming": "Upcoming",
   "shellTabInbox": "Inbox",
+  "todayCount": "{count, plural, =1{1 task} other{{count} tasks}}",
+  "@todayCount": {
+    "description": "Under Today's title: how many tasks are overdue or due today.",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
   "browseProfile": "Profile",
   "browseProfileHint": "Your account, how you sign in and your public profile",
   "shellTabBrowse": "Browse",

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

@@ -154,6 +154,12 @@ abstract class AppLocalizations {
   /// **'Inbox'**
   String get shellTabInbox;
 
+  /// Under Today's title: how many tasks are overdue or due today.
+  ///
+  /// In en, this message translates to:
+  /// **'{count, plural, =1{1 task} other{{count} tasks}}'**
+  String todayCount(int count);
+
   /// No description provided for @browseProfile.
   ///
   /// In en, this message translates to:

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

@@ -38,6 +38,17 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get shellTabInbox => 'Eingang';
 
+  @override
+  String todayCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: '$count Aufgaben',
+      one: '1 Aufgabe',
+    );
+    return '$_temp0';
+  }
+
   @override
   String get browseProfile => 'Profil';
 

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

@@ -38,6 +38,17 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get shellTabInbox => 'Inbox';
 
+  @override
+  String todayCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: '$count tasks',
+      one: '1 task',
+    );
+    return '$_temp0';
+  }
+
   @override
   String get browseProfile => 'Profile';