Update docs and screenshots

backend/app/core/database.py

@@ -0,0 +1,45 @@
+from collections.abc import AsyncIterator
+
+from sqlalchemy import event, text
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+
+from app.core.config import get_settings
+from app.models.base import Base
+
+settings = get_settings()
+engine = create_async_engine(settings.database_url, future=True)
+SessionLocal = async_sessionmaker(engine, expire_on_commit=False, class_=AsyncSession)
+
+
+@event.listens_for(engine.sync_engine, "connect")
+def _enable_sqlite_pragmas(dbapi_connection, _connection_record) -> None:  # type: ignore[no-untyped-def]
+    cursor = dbapi_connection.cursor()
+    cursor.execute("PRAGMA journal_mode=WAL;")
+    cursor.execute("PRAGMA foreign_keys=ON;")
+    cursor.close()
+
+
+async def init_database() -> None:
+    async with engine.begin() as connection:
+        await connection.execute(text("PRAGMA journal_mode=WAL;"))
+        await connection.run_sync(Base.metadata.create_all)
+        await _ensure_compatible_schema(connection)
+
+
+async def get_db_session() -> AsyncIterator[AsyncSession]:
+    async with SessionLocal() as session:
+        yield session
+
+
+async def _ensure_compatible_schema(connection) -> None:  # type: ignore[no-untyped-def]
+    def sync_ensure(sync_connection) -> None:  # type: ignore[no-untyped-def]
+        scene_columns = {
+            row[1]
+            for row in sync_connection.exec_driver_sql("PRAGMA table_info('scenes')").fetchall()
+        }
+        if "targets" not in scene_columns:
+            sync_connection.exec_driver_sql(
+                "ALTER TABLE scenes ADD COLUMN targets JSON NOT NULL DEFAULT '[]'"
+            )
+
+    await connection.run_sync(sync_ensure)