Fix red develop b99c7552f98b

The merge lane found `develop` red at `b99c7552f98b435b8e6c01113aa2e0a0657401ff` on its own: no queued PR merges until it is fixed. Failing (tests and gate stages): - `mirror-trees-strict` - `community-edition-tooling-suite` - `mirror-sensitive-content-suite` - `jaahd-bundle-build-selftest` The whole gate log: artifact `12127` on lane task 11269. 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: removed 2 internal task refs from mirrored code (3 mirror/CE stages) and updated the stale postinst ordering test. Local suites + quick gate green; PR #7339 queued to the merge lane. Memory: none applied.