fix: guna disk('public') dan preview route untuk papar imej di show.blade.php

- Tab QR: Storage::disk('public')->url() — selaras dengan fix QrCodeService
- Tab Template: guna route preview (controller baca dari private disk)
  Storage::url() tanpa disk pada private storage tidak boleh diakses terus

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

resources/views/admin/programs/show.blade.php

@@ -168,7 +168,7 @@
     <div class="tab-pane fade" id="tab-qr">
         @if($program->qrCode)
         <div class="text-center py-3">
-            <img src="{{ Storage::url($program->qrCode->qr_image_path) }}"
+            <img src="{{ Storage::disk('public')->url($program->qrCode->qr_image_path) }}"
                  alt="QR Code" class="img-fluid mb-3" style="max-width:220px;">
             <div class="d-flex justify-content-center gap-2">
                 <a href="{{ route('admin.programs.qr.download', $program) }}" class="btn btn-sm btn-outline-primary">
@@ -210,7 +210,7 @@
             </a>
         </div>
         <div class="text-center">
-            <img src="{{ Storage::url($program->certificateTemplate->image_path) }}"
+            <img src="{{ route('admin.programs.template.preview', $program) }}"
                  alt="Template" class="img-fluid rounded border" style="max-height:300px;">
         </div>
         @else