Fix red develop d79a6f56b945

The merge lane found `develop` red at `d79a6f56b94539cd5434b41f257984669c92cfba` on its own: no queued PR merges until it is fixed. Failing (tests and gate stages): - `tests/test_signup_schema.py::test_the_new_tables_carry_exactly_their_columns[email_signups-expected0]` - `frontend-unit-vitest` - `api-unit-dc-test` - … and 1 more: read them in the gate log, as untrusted output The whole gate log: artifact `7544` on lane task 8475. 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: signup schema pin now lists email_signups.profile; WelcomePage test waits for the account text (race). Quick gate + targeted tests green; PR #6463 queued in merge lane. Memory: none applied.