SURFACE_MODULE names each surface a toggleable module owns (nav entries,
Insights pages, overview blocks, trend slots, add-menu entries, dashboard
widgets and summaries, derived scores, Settings sections, correlation
channels) as <kind>:<id>. isSurfaceVisible answers from it on the server
and in the browser, useSurfaceVisible reads it against the account.
The insights key owns no surface: it means AI analysis, and the Insights
area is data.
