Fix red develop 5e262101e561

The merge lane found `develop` red at `5e262101e561ec5a6f9f18b44a07881494443c66` on its own: no queued PR merges until it is fixed. Failing (tests and gate stages): - `community-edition-tooling-suite` The whole gate log: artifact `11501` on lane task 10871. Make `develop` pass its full gate again. Open a PR as usual: the merge lane merges a PR that fixes some of these and adds no failure even while `develop` is red.

Fixed red develop: CE edition map no longer resolves via a stray /tmp/.git on the lane host (build_tree._map_root falls back to its own tree). Reproduced and fixed; quick gate + 114 CE/editions tests green. PR #7208 queued. Memory: none applied.