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/Http/Controllers/NudgeController.php

@@ -44,7 +44,7 @@ class NudgeController extends Controller
             ->exists();
 
         if ($recentNudge) {
-            return back()->with('flash', ['type' => 'warning', 'message' => 'Relance déjà envoyée récemment']);
+            return back()->with('flash', ['type' => 'warning', 'message' => 'Notification déjà envoyée récemment']);
         }
 
         $assignee->notify(new NudgeNotification($declaration, $request->user()));
@@ -56,6 +56,6 @@ class NudgeController extends Controller
 
         Cache::forget("user:{$assignee->id}:workspace:{$workspace->id}:unread_notifications");
 
-        return back()->with('flash', ['type' => 'success', 'message' => 'Relance envoyée à '.$assignee->name]);
+        return back()->with('flash', ['type' => 'success', 'message' => 'Notification envoyée à '.$assignee->name]);
     }
 }