fix(v2-import): namespace source identity for snapshot upserts

apps/competitions/migrations/0004_competition_source_namespaced_uid.py

@@ -0,0 +1,35 @@
+# Generated by Django 5.2.12 on 2026-03-13 15:08
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("competitions", "0003_competition_source_uid_season_source_uid_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="competition",
+            name="source_name",
+            field=models.CharField(blank=True, default="", max_length=120),
+        ),
+        migrations.AlterField(
+            model_name="competition",
+            name="source_uid",
+            field=models.CharField(blank=True, max_length=120, null=True),
+        ),
+        migrations.AddConstraint(
+            model_name="competition",
+            constraint=models.UniqueConstraint(
+                condition=models.Q(source_uid__isnull=False) & ~models.Q(source_uid=""),
+                fields=("source_name", "source_uid"),
+                name="uq_competition_source_namespace_uid",
+            ),
+        ),
+        migrations.AddIndex(
+            model_name="competition",
+            index=models.Index(fields=["source_name", "source_uid"], name="competition_source__4c5f3d_idx"),
+        ),
+    ]