fixes

backend/app/database.py

@@ -1,3 +1,4 @@
+from sqlalchemy import event
 from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine, async_sessionmaker
 from sqlalchemy.orm import DeclarativeBase
 from app.config import settings
@@ -6,6 +7,17 @@ engine = create_async_engine(settings.database_url, echo=False)
 SessionLocal = async_sessionmaker(engine, expire_on_commit=False)
 
 
+# Enable WAL mode so concurrent reads don't block on an open write transaction.
+# Also set a generous busy timeout so transient lock contention retries instead
+# of immediately raising OperationalError.
+@event.listens_for(engine.sync_engine, "connect")
+def _set_sqlite_pragmas(dbapi_conn, _record):
+    cursor = dbapi_conn.cursor()
+    cursor.execute("PRAGMA journal_mode=WAL")
+    cursor.execute("PRAGMA busy_timeout=10000")  # 10 s
+    cursor.close()
+
+
 class Base(DeclarativeBase):
     pass