feat(jobs): implement encrypted queue jobs

- Add ShouldBeEncrypted interface to all queue jobs to encrypt sensitive
  job payloads
- Configure explicit retry policies for messaging jobs (5 attempts,
  10-second backoff)

app/Jobs/SendMessageToSlackJob.php

@@ -4,16 +4,27 @@ namespace App\Jobs;
 
 use App\Notifications\Dto\SlackMessage;
 use Illuminate\Bus\Queueable;
+use Illuminate\Contracts\Queue\ShouldBeEncrypted;
 use Illuminate\Contracts\Queue\ShouldQueue;
 use Illuminate\Foundation\Bus\Dispatchable;
 use Illuminate\Queue\InteractsWithQueue;
 use Illuminate\Queue\SerializesModels;
 use Illuminate\Support\Facades\Http;
 
-class SendMessageToSlackJob implements ShouldQueue
+class SendMessageToSlackJob implements ShouldBeEncrypted, ShouldQueue
 {
     use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;
 
+    /**
+     * The number of times the job may be attempted.
+     */
+    public $tries = 5;
+
+    /**
+     * The number of seconds to wait before retrying the job.
+     */
+    public $backoff = 10;
+
     public function __construct(
         private SlackMessage $message,
         private string $webhookUrl