The help pages never say "pause", so organizers looking for it miss Close or reopen a signup #653

Needs your OK: this changes the summary and search description of the help page "Close or reopen a signup". Swap pipeline:proposed for pipeline:ready to have it built.

What happens

• The help pages have no search. An organizer finds a page by its title and its one-line summary on /help.
• "Close or reopen a signup" is the page for stopping sign-ups for a while. Its summary in src/help/articles.ts is "Stop anyone new signing up, and let people sign up again at the same link when you're ready."
• "Pause" isn't anywhere on it: not in its title, summary, description or text, and not anywhere else in src/help.
• A tester looking for it missed it. In the UX walkthrough on Add a help page on closing and reopening a signup #610, a tester wanting to pause sign-ups searched the page for "pause" and "stop sign" and found nothing. They found the page only by reading every title.

Fix, in outline

• Summary: for example, "Pause or stop sign-ups, and let people sign up again at the same link when you're ready."
• Description, which search results and link previews show: for example, "Pause or close your signup so nobody new can sign up, and everyone already signed up keeps their spot. Reopen it later, at the same link." (137 characters.)
• First paragraph of the article: add pausing to when you'd close it. For example: "…when you have enough people, when it's too late to sign up, or to pause sign-ups for a while."

Watch for

• docs/writing-help.md: a "sign-up" is what someone does, and a "signup" is the page. src/help/articles.test.tsx checks the description's length (110 to 160 characters) and the style rules.
• The title stays, so the slug and every link to the page stay the same.
• The button is still Close signup. The page mustn't suggest there's a Pause button.
• CHANGELOG: add a line under Unreleased › Changed.

Choices this makes

• "Pause" goes in the summary, description and first paragraph, not the title. The title names the task by its button, as the other help pages do.
• The wording above, which the owner can edit here first.

Done when

• /help shows the new summary, and the page's meta description includes "Pause".
• The first paragraph mentions pausing sign-ups.
• articles.test.tsx passes.
• pnpm lint && pnpm typecheck && pnpm knip && pnpm test pass.

From the UX walkthrough comment on #610 (#610 (comment)). Checked against src/help on main at 1d4ff3a. https://claude.ai/code/session_01LrYa57fvbqWjZj89iH975K