fix: resolve permission toggle persistence, nudge terminology, and bulk action bugs (Bugs #2-5)

- Fix togglePermission() to always include all permission keys with false defaults
- Add migration to backfill null/empty Manager permissions with config defaults
- Rename nudge UI text from "Relance" to "Notification"/"Notifier" across 8 files
- Fix select-all checkbox and show checkboxes on all declaration rows
- Remove en_attente_client status restriction from BulkNotificationController

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/Notifications/NudgeNotification.php

@@ -48,6 +48,7 @@ class NudgeNotification extends Notification implements ShouldQueue
 
     public function toMail(object $notifiable): NudgeNotificationMail
     {
-        return new NudgeNotificationMail($this->declaration, $this->sender);
+        return (new NudgeNotificationMail($this->declaration, $this->sender))
+            ->to($notifiable->email);
     }
 }