style: use SQLAlchemy 2.0 select() in sync test helpers

Match the select()/scalars() convention already used throughout
app/db/repositories.py instead of the legacy Query API.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tests/sync/test_manager.py

@@ -1,6 +1,7 @@
 from pathlib import Path
 
 import pytest
+from sqlalchemy import select
 
 from app.db.models import ActivityStatus, SyncRun, SyncRunStatus, SyncUser
 
@@ -78,7 +79,7 @@ async def test_sync_run_repository_wiring_records_run(manager, seeded_user: Sync
     await manager.sync_user(seeded_user.id)
 
     with session_factory() as session:
-        runs = session.query(SyncRun).filter_by(user_id=seeded_user.id).all()
+        runs = list(session.scalars(select(SyncRun).where(SyncRun.user_id == seeded_user.id)))
         assert len(runs) == 1
         run = runs[0]
         assert run.status == SyncRunStatus.SUCCESS