Add v2 snapshot schema validation and import_snapshots command

apps/ingestion/migrations/0004_importfile_snapshot_date_importfile_source_name_and_more.py

@@ -0,0 +1,27 @@
+# Generated by Django 5.2.12 on 2026-03-13 12:59
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('ingestion', '0003_importrun_importfile_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='importfile',
+            name='snapshot_date',
+            field=models.DateField(blank=True, null=True),
+        ),
+        migrations.AddField(
+            model_name='importfile',
+            name='source_name',
+            field=models.CharField(blank=True, max_length=120),
+        ),
+        migrations.AddIndex(
+            model_name='importfile',
+            index=models.Index(fields=['source_name', 'snapshot_date'], name='ingestion_i_source__de6843_idx'),
+        ),
+    ]