code-to10 v6 A14 batch2: test E402/F401 cleanup plus touched-file residual E,F cleanup

(cherry picked from commit 1db02545f74c96b3b92be4fc32954659cec1f814)

Reconcile-conflict: A14b E402 imports referencing cloud.handler_core (does not exist here; core methods live in server.py) — kept HEAD imports with incoming's noqa: E402 markers, dropped the unused core_mod import (verified unused elsewhere in both files).

cloud/tests/test_v2cov_server_handlers2.py

@@ -19,7 +19,6 @@ logic -- validation, permission checks via the real AuthStore,
 quota gates, driver result shaping -- runs for real.
 """
 
-import json
 import os
 import sqlite3
 import sys
@@ -33,9 +32,9 @@ from unittest import mock
 REPO_ROOT = Path(__file__).resolve().parents[2]
 sys.path.insert(0, str(REPO_ROOT))
 
-import cloud.server as server_mod
-from cloud.server import CloudControlPlaneHandler, _auth_store, init_db
-from cloud.sub2api import Sub2apiError as _Sub2apiError
+import cloud.server as server_mod  # noqa: E402
+from cloud.server import CloudControlPlaneHandler, _auth_store, init_db  # noqa: E402
+from cloud.sub2api import Sub2apiError as _Sub2apiError  # noqa: E402
 
 
 def _handler(db_path, upload_dir=None):