fix(todo): the permission to notify asked wherever a reminder is planned, and Settings saying while it is off (ADR 0033, D31)

On a fresh install Todo's reminders never showed: the permission to notify
(Android 13's POST_NOTIFICATIONS, iOS' and macOS' alert) was asked only
where a task's sheet chose its first reminder, so reminders typed in quick
add, added by the automatic reminder or brought by sync were scheduled and
dropped by the system without a word.

Now NotificationAccess, the device's, reads whether notifications are
allowed whenever the plan holds a reminder and asks where they aren't,
once an app start, so that a refusal isn't met with the dialog again and
again; the task sheet asks through it. While reminders are planned and
notifications are off, Settings' Reminders say so, with Turn on: asked
again, and where that doesn't allow it, the system's notification settings
of the app opened (flutter_local_notifications' own call, nothing added).
Read again whenever the app comes back.

Whats-New: Todo asks to notify as soon as there is a reminder, and Settings › Reminders shows when notifications are off, with Turn on.
Whats-New-De: Todo fragt nach Benachrichtigungen, sobald es eine Erinnerung gibt, und Einstellungen › Erinnerungen zeigt, wenn sie aus sind, mit Einschalten.

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_en.arb

@@ -812,6 +812,18 @@
       }
     }
   },
+  "notificationsOffTitle": "Notifications are off",
+  "@notificationsOffTitle": {
+    "description": "Settings' Reminders while notifications are off and reminders are planned (ADR 0033, D31)."
+  },
+  "notificationsOffHint": "Reminders can't show until Halkyon Todo may notify you.",
+  "@notificationsOffHint": {
+    "description": "Settings' Reminders while notifications are off and reminders are planned (ADR 0033, D31)."
+  },
+  "notificationsTurnOn": "Turn on",
+  "@notificationsTurnOn": {
+    "description": "Settings' Reminders while notifications are off and reminders are planned (ADR 0033, D31)."
+  },
   "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.",