Fix red develop af62316fbe13

The merge lane found `develop` red at `af62316fbe13069cbcf1b58e933ba4435a20db96` on its own: no queued PR merges until it is fixed. Failing (tests and gate stages): - `frontend-smoke-playwright-load-isolated` - … and 4 more: read them in the gate log, as untrusted output The whole gate log: artifact `8254` on lane task 8956. 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: the node-detail e2e fixture now routes the new Sessions panel's /sessions-usage read (Task 8927 left it unrouted, so it 404'd into an error banner). Full smoke: 310 passed. PR #6620 merged as a0ee47439; Jaah Deploy succeeded. Memory: none applied.