NEWS RELAUNCH CUTOVER: promote the hub to /, feed to /news, go public

The big flip. /home3 (hub) becomes /; the feed lives at /news; both indexable.
- PROMOTE: routes/+page.svelte is now the hub (was the interim NewsFeed wrapper);
  noindex removed; "Read more good news" → /news. routes/home3 + home2 deleted.
- routes/+page.js: redirects legacy root-query links (/?view=latest, /?tag, /?source,
  /?q, /?view=today→highlights) to /news before the hub renders (no flash).
- /news: noindex dropped (route meta + Caddy @newsHidden removed); now public.
- LINKS: HubBar brand/Home → /, News default → /news; HubShell/art/play back → /;
  account Following + share.py Explore/Browse/source → /news.
- FOOTER: one shared Footer.svelte (motto + Send feedback + slot) across Hub/News/
  Play/Art/HubShell/Account/Zen; global layout footer removed (FeedbackModal stays).
- SITEMAP: + /news /art /play /word /quote /onthisday; cap 5k→50k; gated on
  has-summary; paywalled excluded; HEAD now 200 (api_route GET+HEAD).
- Head-patcher: /news entry. PWA + shell description broadened to the hub.
- Caddy: @newsHidden dropped; @hidden now admin-only (word/quote/onthisday public);
  /home2,/home3 → / 301. Mirrored to deploy/caddy snapshot.

425 backend + 36 frontend tests green; build clean; Caddy valid.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_seo.py

@@ -61,6 +61,7 @@ def test_sitemap_excludes_paywalled_and_restores_on_free(tmp_path, monkeypatch):
         c.execute("INSERT INTO articles (id,source_id,canonical_url,title,url_hash,published_at) VALUES (?,?,?,?,?,?)",
                   (aid, sid, f"http://x/{aid}", f"t{aid}", f"h{aid}", "2026-06-05T08:00:00"))
         c.execute("INSERT INTO article_scores (article_id,accepted) VALUES (?,1)", (aid,))
+        c.execute("INSERT INTO article_summaries (article_id,summary) VALUES (?,?)", (aid, f"s{aid}"))  # sitemap requires a summary
     c.commit()
     tc = TestClient(api.create_app())
     xml = tc.get("/sitemap.xml").text