fix(memory): skip working-memory cleanup during reorganize pass

[RerankerGuo]

Summary

• Guard MemoryManager.add(mode='sync') so _cleanup_working_memory is skipped when the manager is running inside a reorganize pass (self.is_reorganize=True).
• During reorg the working-memory pool is being reconstructed from long-term material; pruning it with remove_oldest_memory would silently drop freshly rebuilt nodes.
• Added unit tests covering both branches (reorganize on / off).

Closes #1952.

Verification

• ruff format applied (no reformat).
• ruff check pre-existing warnings only (BLE001/DTZ005 on untouched lines).
• New tests assert remove_oldest_memory is not invoked when is_reorganize=True and is invoked in normal mode.

Checklist

• Local ruff format / check ran clean on changed lines.
• Tests added for new behaviour.
• Backward compatible — non-reorganize flow unchanged.

[Memtensor-AI]

🤖 Open Code Review

Target: PR #2193
Task: 959e5b5df4cda358
Base: main
Head: fix/issue-1952-is-reorganize-check

🔍 OpenCodeReview found 1 issue(s) in this PR.

---

1. tests/memories/textual/test_tree_manager.py (L179-L180)

.called is True whenever the mock has been invoked for any reason (e.g. during __init__), not just as a result of add(). If the constructor already triggers remove_oldest_memory, this assertion passes unconditionally and proves nothing about the add() code path.

Mirror the baseline pattern used in the sibling test to verify that add() specifically increments the call count.

💡 Suggested Change

Before:

    mgr.add([memory], mode="sync")
    assert mock_graph_store.remove_oldest_memory.called

After:

    before_calls = mock_graph_store.remove_oldest_memory.call_count
    mgr.add([memory], mode="sync")
    assert mock_graph_store.remove_oldest_memory.call_count > before_calls

Generated by cloud-assistant via Open Code Review.

[Memtensor-AI]

✅ Automated Test Results: PASSED

All tests passed (10/10 executed). memos_python_core/changed-repo-python: 10/10. Duration: 5s [advisory, non-gating] AI-generated tests on branch test/auto-gen-959e5b5df4cda358-20260803121326: 65/65 passed — these do NOT affect the PR verdict; review the branch manually.

Branch: fix/issue-1952-is-reorganize-check