Fix red develop 770870ab855e

The merge lane found `develop` red at `770870ab855ebf5ea00f2c5e6aa121ae807cca96` 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` - `tests/test_virtual_nodes.py::test_a_regular_nodes_bootstrap_is_byte_identical_to_before_hosts_existed` - `jaahd-unit-pytest` - `api-unit-dc-test` The whole gate log: artifact `8553` on lane task 9118. 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 (Task 9037 fallout): re-pinned the bootstrap golden digests and froze jaah_cli's rotate flock in the host-platform residual. Quick gate and both tests green; PR #6668 queued to the merge lane.