Add Alembic migration foundation

app/db.py

@@ -1,6 +1,6 @@
 from typing import Generator
 
-from sqlalchemy import create_engine, event, text
+from sqlalchemy import create_engine, event
 from sqlalchemy.engine import make_url
 from sqlalchemy.orm import DeclarativeBase, Session, sessionmaker
 
@@ -62,47 +62,14 @@ def get_db() -> Generator[Session, None, None]:
 
 
 def init_db(database_url: str | None = None) -> None:
-    from app import models
+    from app import models  # noqa: F401 — register models on Base.metadata
 
     if engine is None or database_url is not None:
         configure_database(database_url)
 
-    Base.metadata.create_all(bind=engine)
-    _sync_sqlite_image_columns()
+    from app.migrate import verify_schema_is_current
+
+    resolved_url = str(engine.url)
+    verify_schema_is_current(resolved_url)
 
 
-def _sync_sqlite_image_columns() -> None:
-    if engine is None or engine.dialect.name != "sqlite":
-        return
-
-    image_columns = {
-        "boxes": {
-            "image_blob": "BLOB",
-            "image_mime_type": "VARCHAR(50)",
-            "image_width": "INTEGER",
-            "image_height": "INTEGER",
-        },
-        "items": {
-            "image_blob": "BLOB",
-            "image_mime_type": "VARCHAR(50)",
-            "image_width": "INTEGER",
-            "image_height": "INTEGER",
-        },
-        "subitems": {
-            "image_blob": "BLOB",
-            "image_mime_type": "VARCHAR(50)",
-            "image_width": "INTEGER",
-            "image_height": "INTEGER",
-        },
-    }
-
-    with engine.begin() as connection:
-        for table_name, columns in image_columns.items():
-            existing_columns = {
-                row[1] for row in connection.execute(text(f"PRAGMA table_info({table_name})"))
-            }
-            for column_name, column_type in columns.items():
-                if column_name not in existing_columns:
-                    connection.execute(
-                        text(f"ALTER TABLE {table_name} ADD COLUMN {column_name} {column_type}")
-                    )