Fix red develop afdd6fa3313a

The merge lane found `develop` red at `afdd6fa3313a75fb707f938b6b3c22ff3bbc5f49` on its own: no queued PR merges until it is fixed. Failing (tests and gate stages): - `tests/test_host_platform_guard.py::test_no_host_specific_spelling_outside_the_seam_beyond_the_frozen_residual` - `jaahd-unit-pytest` The whole gate log: artifact `12211` on lane task 11302. 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: froze the account Delete's procfs session killer (accounts.py, run `python3 -I`, cannot import the seam) in the host-platform guard RESIDUAL. Guard 4/4 passing, quick gate green; PR #7359 queued to the merge lane. Memory: none applied.