Write documentation for multiple sections

Docs-writer run. Follow apps/docs/WRITER.md on develop. Do each item that is due, all in ONE PR: 1. Screens: one console feature's reference page. 2. Guides: one Get started, Using Jaah or FAQ item. 3. Changelog: the next batch of prod promotions 4. Reference: the Jaah API and Real-time reference against the code. Sign in only through the capture helper. Nothing due: end with no PR.

Docs run: refreshed the invitations page and recaptured /users/new on prod; fixed the Rate limits page's wait advice. Guides and Changelog not due. Quick gate green; PR #7986 queued in the merge lane. Visual check done: screenshots legible. Memory: none applied.