fix(logic): isolate atomic batch counters and token sync fields

tests/test_account_token_sync_status.py

@@ -0,0 +1,72 @@
+from src.database import crud
+from src.database.session import DatabaseSessionManager
+
+
+def test_create_account_marks_token_sync_pending_when_tokens_persist(tmp_path):
+    manager = DatabaseSessionManager(f"sqlite:///{tmp_path}/test.db")
+    manager.create_tables()
+    manager.migrate_tables()
+
+    with manager.session_scope() as session:
+        account = crud.create_account(
+            session,
+            email="sync@example.com",
+            email_service="tempmail",
+            access_token="access-token",
+            refresh_token="refresh-token",
+        )
+
+        assert account.token_sync_status == "pending"
+        assert account.token_sync_updated_at is not None
+
+
+def test_update_account_marks_token_sync_pending_when_tokens_change(tmp_path):
+    manager = DatabaseSessionManager(f"sqlite:///{tmp_path}/test.db")
+    manager.create_tables()
+    manager.migrate_tables()
+
+    with manager.session_scope() as session:
+        account = crud.create_account(
+            session,
+            email="nosync@example.com",
+            email_service="tempmail",
+        )
+
+        assert account.token_sync_status == "not_ready"
+
+        updated = crud.update_account(
+            session,
+            account.id,
+            access_token="new-access-token",
+        )
+
+        assert updated is not None
+        assert updated.token_sync_status == "pending"
+        assert updated.token_sync_updated_at is not None
+
+
+def test_update_account_preserves_pending_status_when_other_tokens_remain(tmp_path):
+    manager = DatabaseSessionManager(f"sqlite:///{tmp_path}/test.db")
+    manager.create_tables()
+    manager.migrate_tables()
+
+    with manager.session_scope() as session:
+        account = crud.create_account(
+            session,
+            email="partial-sync@example.com",
+            email_service="tempmail",
+            access_token="access-token",
+            refresh_token="refresh-token",
+        )
+
+        updated = crud.update_account(
+            session,
+            account.id,
+            refresh_token="",
+        )
+
+        assert updated is not None
+        assert updated.access_token == "access-token"
+        assert updated.refresh_token == ""
+        assert updated.token_sync_status == "pending"
+        assert updated.token_sync_updated_at is not None

tests/test_batch_task_manager.py

@@ -0,0 +1,21 @@
+from concurrent.futures import ThreadPoolExecutor
+
+from src.web.task_manager import task_manager
+
+
+def test_record_batch_task_result_is_atomic_under_threads():
+    batch_id = "batch-atomic-test"
+    task_manager.init_batch(batch_id, 100)
+
+    statuses = ["completed"] * 60 + ["failed"] * 40
+
+    with ThreadPoolExecutor(max_workers=16) as executor:
+        list(executor.map(lambda status: task_manager.record_batch_task_result(batch_id, status), statuses))
+
+    snapshot = task_manager.get_batch_status(batch_id)
+
+    assert snapshot is not None
+    assert snapshot["completed"] == 100
+    assert snapshot["success"] == 60
+    assert snapshot["failed"] == 40
+    assert snapshot["skipped"] == 0