feat: WorkOrderPhoto izolacija, upload modal i SN stupac u tablici putnih naloga

- Dodan WorkOrderPhoto model (FK na WorkOrder, odvojen od VehicleServicePhoto)
- Migracija 0022_workorderphoto
- WorkOrderViewSet.images action refaktoriran: GET/POST koristi WorkOrderPhoto
- WorkOrderPhotoSerializer dodan u serializers.py
- WorkOrderPhotoInline dodan u admin.py
- Novi WorkOrderPhotoUpload.jsx modal s podrskom za onBack prop i z-[60]
- WorkOrderDetailModal: gumb Dodaj fotografije u editMode, photoUploadOpen state,
  ispravljen onSuccess callback (map na URL stringove), reset pri zatvaranju
- FleetDashboardShell: stupac SN u tablici putnih naloga (craneInfo.crane_serial_number)
- fleetDashboardStore: uklonjen dupli toast iz uploadWorkOrderPhoto
- Dodan test test_work_order_images_endpoint.py

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

backend/modules/fleet/migrations/0022_workorderphoto.py

@@ -0,0 +1,43 @@
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import uuid
+
+
+def work_order_photo_upload_to(instance, filename):
+    vehicle_reg = 'unknown'
+    try:
+        vehicle_reg = instance.work_order.vehicle.registration_number
+    except Exception:
+        vehicle_reg = 'unknown'
+    unique_name = f"{uuid.uuid4().hex}_{filename}"
+    return f"fleet/{vehicle_reg}/work_order_photos/{unique_name}"
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fleet', '0021_alter_vehicle_assigned_servicer_many_to_one'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='WorkOrderPhoto',
+            fields=[
+                ('id', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+                ('image', models.ImageField(upload_to=work_order_photo_upload_to, verbose_name='Fotografija putnog naloga')),
+                ('description', models.CharField(blank=True, max_length=255, verbose_name='Opis')),
+                ('is_active', models.BooleanField(default=True, verbose_name='Aktivan')),
+                ('uploaded_by', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='uploaded_work_order_photos', to=settings.AUTH_USER_MODEL, verbose_name='Postavio')),
+                ('work_order', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='photos', to='fleet.workorder', verbose_name='Putni nalog')),
+            ],
+            options={
+                'verbose_name': 'Fotografija putnog naloga',
+                'verbose_name_plural': 'Fotografije putnog naloga',
+                'ordering': ['-created_at'],
+            },
+        ),
+    ]