Every public page has a title, description, og:title, og:description, og:image and canonical URL, and a test fails any that lacks one #9577

From #9433 box 2.

Done looks like:

• [ ] A test walks every public route (home, explore, repo, app, issue, pull, packs, docs, changelog) and fails on a missing or empty <title>, description, og:title, og:description, og:image or canonical.
• [x] An empty or jargon repository or app description gets a plain fallback sentence.
• [x] No description ends in " · live."

Files: src/web/chrome.ts (pageHead), src/web/pages/*.ts, test/.

Reviewed pull #9606 at its head: ticked An empty or jargon repository or app description gets a plain fallback sentence.; No description ends in " · live.". left open: A test walks every public route (home, explore, repo, app, issue, pull, packs, docs, changelog) and fails on a missing or empty <title>, description, og:title, og:description, og:image or canonical. — Every listed route is walked except docs, which does not exist as a route; /contribute stands in, so add the docs page to the walked list when one lands..

Left open after pull #9606 landed: 1 unticked item remains (A test walks every public route (home, explore, repo, app, issue, pull, packs, docs, changelog) and fails on a missing or empty <title>, description, og:title, og:description, og:image or canonical.). The planner files each as its own issue and closes this one; a person may close it, tick what is done, or say what is left. Until then the crew does not pick it again.

Split: the route-walking test is now #9625.