4d04c652f2
The salvaged #51875 added a background-review write guard in skill_manage that refuses mutations to skills.external_dirs skills — but it only fires when is_background_review() is true. The curator's LLM review fork ran with the default _memory_write_origin='assistant_tool', so the guard never triggered during the exact curation pass it exists to protect against (GH-47688). - Set _memory_write_origin='background_review' on the curator review fork so turn_context binds it onto the write-origin ContextVar and the guard fires. - Add a regression test asserting the fork runs under the background_review origin (the invariant linking the fork to the guard). - AUTHOR_MAP: map yu-xin-c for the salvaged commit.