feat(todo): a project's Calendar as a month on wide windows (ADR 0033, D17)

From 720 pixels of the Calendar's own width on, a month grid in place
of the agenda: the month's weeks from the week's first day, the days
of the months beside it muted, each day with as many of its tasks as
fit and the rest counted, opening the day's tasks in a sheet; past
days with their overdue and done tasks. A task held and dropped on
another day moves there (moveTask), a day's free space tapped adds a
task on it, a line tapped opens its task.

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

@@ -231,5 +231,6 @@
   "automaticReminderNone": "Keine",
   "snoozeTitle": "Schlummern für",
   "snoozeMinutes": "{count, plural, =1{1 Minute} other{{count} Minuten}}",
-  "reminderSnooze": "{count} Min. schlummern"
+  "reminderSnooze": "{count} Min. schlummern",
+  "monthMore": "{count} weitere"
 }

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

@@ -734,5 +734,14 @@
         "type": "int"
       }
     }
+  },
+  "monthMore": "{count} more",
+  "@monthMore": {
+    "description": "A project's Calendar as a month on wide windows (ADR 0033, D17): a day's tasks that don't fit.",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
   }
 }

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

@@ -1491,6 +1491,12 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Snooze {count} min'**
   String reminderSnooze(int count);
+
+  /// A project's Calendar as a month on wide windows (ADR 0033, D17): a day's tasks that don't fit.
+  ///
+  /// In en, this message translates to:
+  /// **'{count} more'**
+  String monthMore(int count);
 }
 
 class _AppLocalizationsDelegate

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

@@ -921,4 +921,9 @@ class AppLocalizationsDe extends AppLocalizations {
   String reminderSnooze(int count) {
     return '$count Min. schlummern';
   }
+
+  @override
+  String monthMore(int count) {
+    return '$count weitere';
+  }
 }

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

@@ -920,6 +920,11 @@ class AppLocalizationsEn extends AppLocalizations {
   String reminderSnooze(int count) {
     return 'Snooze $count min';
   }
+
+  @override
+  String monthMore(int count) {
+    return '$count more';
+  }
 }
 
 /// The translations for English, as used in the United Kingdom (`en_GB`).