feat: email blast for certificates (Fasa 8)

- CertificateReadyMail: Mailable with Malay HTML email template
- SendCertificateEmailJob: dispatch per-certificate email, log to email_logs
- Email template: HTML with download link, program details, branding

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/Jobs/SendCertificateEmailJob.php

@@ -2,26 +2,69 @@
 
 namespace App\Jobs;
 
+use App\Mail\CertificateReadyMail;
 use App\Models\Certificate;
+use App\Models\EmailLog;
 use App\Models\Program;
 use Illuminate\Bus\Queueable;
 use Illuminate\Contracts\Queue\ShouldQueue;
 use Illuminate\Foundation\Bus\Dispatchable;
 use Illuminate\Queue\InteractsWithQueue;
 use Illuminate\Queue\SerializesModels;
+use Illuminate\Support\Facades\Mail;
 
 class SendCertificateEmailJob implements ShouldQueue
 {
     use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;
 
-    public int $tries = 3;
+    public int $tries   = 3;
     public int $backoff = 60;
 
     public function __construct(public readonly Certificate $certificate) {}
 
     public function handle(): void
     {
-        // Implemented in Fasa 8 — email blast
+        $cert = $this->certificate->refresh();
+        $cert->load(['participant', 'program']);
+
+        $email = $cert->participant->email;
+
+        if (! $email) {
+            return;
+        }
+
+        try {
+            Mail::to($email)->send(new CertificateReadyMail($cert));
+
+            $cert->update([
+                'status'     => 'emailed',
+                'emailed_at' => now(),
+            ]);
+
+            EmailLog::create([
+                'program_id'     => $cert->program_id,
+                'participant_id' => $cert->participant_id,
+                'certificate_id' => $cert->id,
+                'recipient_email'=> $email,
+                'subject'        => 'Sijil Digital Program — ' . $cert->program->title,
+                'email_type'     => 'certificate_ready',
+                'status'         => 'sent',
+                'sent_at'        => now(),
+            ]);
+        } catch (\Throwable $e) {
+            EmailLog::create([
+                'program_id'     => $cert->program_id,
+                'participant_id' => $cert->participant_id,
+                'certificate_id' => $cert->id,
+                'recipient_email'=> $email,
+                'subject'        => 'Sijil Digital Program — ' . $cert->program->title,
+                'email_type'     => 'certificate_ready',
+                'status'         => 'failed',
+                'error_message'  => $e->getMessage(),
+            ]);
+
+            throw $e;
+        }
     }
 
     public static function dispatchBatch(Program $program): void
@@ -29,6 +72,11 @@ class SendCertificateEmailJob implements ShouldQueue
         $program->certificates()
             ->whereIn('status', ['generated'])
             ->whereNull('emailed_at')
-            ->each(fn($cert) => static::dispatch($cert));
+            ->with('participant')
+            ->each(function (Certificate $cert) {
+                if ($cert->participant->email) {
+                    static::dispatch($cert);
+                }
+            });
     }
 }