Fix red develop 936f302e5218

The merge lane found `develop` red at `936f302e5218234d28f4a9b69c015efde6e41c43` on its own: no queued PR merges until it is fixed. Failing (tests and gate stages): - `tests/support_agent/test_support_entity_tools.py::test_every_new_tool_leaves_the_database_unchanged_but_its_marked_read` - `api-unit-dc-test` The whole gate log: artifact `14276` on lane task 12625. 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 flaky read-only tools test: the tenancy exclusion-log flush wrote inside its window (same exclusion as the sibling test). support_agent suite + quick gate green; PR #7726 queued in the merge lane.