refactor: clean up scaffolding backend

backend/letters/migrations/0007_alter_letter_public_id.py

@@ -0,0 +1,19 @@
+# Generated by Django 6.0.4 on 2026-04-15 18:13
+
+import uuid
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("letters", "0006_letterimage"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="letter",
+            name="public_id",
+            field=models.UUIDField(default=uuid.uuid4, primary_key=True, serialize=False),
+        ),
+    ]