test(storage): align semantic processor fakes with pathlock lease and localized overview heading

[huangruiteng]

Problem

Three stale test doubles/assertions in tests/storage fail on main at 674f5e60:

1. test_semantic_processor_language.py::test_overview_generation_language_flow[zh-CN] — the semantic/overview_generation.yaml template renders the section heading as 简要描述 for zh-CN and Brief Description otherwise (template line 59), but the test always asserted "Brief Description", so the zh-CN parametrization failed while en/ja passed.
2. test_semantic_processor_mv_vector_store.py::test_mv_canonicalizes_user_shorthand_before_vector_update — VikingFS.mv now acquires a pathlock lease via _async_agfs.pathlock_acquire_batch and passes the resulting lease dict through _pathlock_fs_ctx. The test left that mock auto-returning an AsyncMock, which _pathlock_fs_ctx rejects with ValueError: lease_ref must be a non-empty string or lease dictionary.
3. test_semantic_queue_memory_dedupe.py::test_stale_memory_semantic_write_is_skipped — write_semantic_sidecars now calls VikingFS.write_file(..., lease_ref=...), but the test's _FakeVikingFS.write_file did not accept the kwarg (TypeError: ... got an unexpected keyword argument 'lease_ref').

These are the same stale-test-fake class as already-fixed #3758/#3835/#3839.

Change

Test-only:

• Assert the language-appropriate overview heading (简要描述 for zh-CN).
• Stub pathlock_acquire_batch to return a {'lease_ref': 'lease-1'} dict in the mv test.
• Add lease_ref=None to _FakeVikingFS.write_file.

No product code changed.

Tests

PYTHONPATH="$PWD" .venv/bin/python -m pytest   tests/storage/test_semantic_processor_language.py   tests/storage/test_semantic_processor_mv_vector_store.py   tests/storage/test_semantic_queue_memory_dedupe.py   -p no:cacheprovider --no-cov -q
74 passed, 4 warnings in 0.49s

The remaining failures under tests/storage are covered by other open Draft PRs (#3807 openGauss update_data, #3808 qdrant caplog, #3813 mock adapter, #3777 volcengine update_data) or are environmental (bulk_upsert missing PersistStore native symbol).

[huangruiteng]

Closed by the Ark/LoopX community-hygiene audit: this Draft was produced from a local test sweep without an accepted upstream issue or maintainer-owned task, so it is outside the current issue-fix qualification boundary. The source branch is intentionally retained; this PR may be reopened after explicit issue qualification and a fresh competing-PR check.