Demo: use the script itself as the migrations module

demo/main.py

@@ -10,9 +10,9 @@ lives in this file.
 
 import asyncio
 import logging
+import sys
 from datetime import UTC, datetime, timedelta
 from pathlib import Path
-from types import ModuleType
 
 import msgspec
 
@@ -44,13 +44,10 @@ def migrate_v1(d: dict) -> None:
     d["settings"] = {"theme": "dark"}
 
 
-migrations = ModuleType("demo_migrations")
-migrations.migrate_v1 = migrate_v1
-
 # Phase 1 instance: default logging, original schema.
 kanta_v0 = Kanta(DB, DataV1())
-# Phase 2 instance: migrations and a custom log header.
-kanta_v1 = Kanta(DB, Data(), migrations=migrations)
+# Phase 2 instance: migrations (scanned from this script) and a custom header.
+kanta_v1 = Kanta(DB, Data(), migrations=sys.modules[__name__])
 
 _now = datetime(2026, 8, 6, tzinfo=UTC)