The ai-quality, assistant, and coach-feedback admin sections were three
separate navigation entries for one coherent coach-quality concern. Fold
them into a single "Coach" section that stacks the assistant surface
toggles, the server-key + module-availability operator config, and both
feedback-quality tables (Coach + Insights). Drop the three old slugs and
their section copy; add admin.section.coach.* across all six locales.