feat(seo-data,seo,geo): R2 — refuse to score what JS paints; no Playwright

Arbitrated (user): honest refusal on SPA, no headless browser.

STEP 2 has recorded `RENDERING: SSR/SSG/SPA/hybrid` since forever and NOTHING
ever acted on it. (The inventory claimed a "SPA severely limited" §0 flag
compensated — it does not exist. Seventh subagent claim this branch has had to
disprove.) So on a client-rendered site the FULL audit curls an empty shell,
every meta/H1/JSON-LD check reports "missing", and the agent emits a page of
false findings — plus a bundle that would "fix" tags which already exist.

rendercheck reads the verdict from what the server SENT. package.json cannot
tell a React SPA from a Next.js SSR app; the served bytes can. Stdlib only.

The refusal is the point:
- client-rendered → On-page is N/A, excluded from the weighted global, NOT
  scored zero. A zero says "your on-page is bad"; N/A says "we could not see
  it". Only one is true, and /client-handover gates on this number.
- No bundle item may come from a live on-page check on such a site.
- The report still says what IS auditable (robots, sitemap, headers, config,
  CrUX field data — real users, hydration included — GSC, legal, images)
  rather than returning an empty verdict.
- geo refuses Content Shape the same way, and states the sharper fact: AI
  crawlers are WORSE at JS than Googlebot. GPTBot/PerplexityBot/ClaudeBot
  fetch HTML and largely do not execute it, so a client-rendered site is not
  merely unauditable by us — it is near-invisible to the engines this audit
  exists to serve. §0 alert + SSR/SSG as the top user action.

Script/style text is not page text: a React shell with a fat inline
window.__INITIAL_STATE__ measures 7 chars. Without that skip a 200 KB bundle
reads as a rich page — the detector would fail exactly where it matters.

Verified on both extremes, not just the happy path: zenquality 7650 chars/1
h1/9 jsonld and lavageangels356 13973/1/1 → server-rendered, no warning; a
Vite/React shell fixture → client-rendered, 7/0/0, warned.

seo-data 136 -> 144 pass, 0 fail; full suite green; shellcheck + py_compile
clean.

lib/seo-data/fetch.sh

@@ -32,6 +32,8 @@ case "$cmd" in
   # No auth, no Google: stdlib-only, runs even without the venv.
   sitemap)
     exec "$PY" "$HERE/sitemap.py" --store "$STORE" "$@" ;;
+  rendercheck)
+    exec "$PY" "$HERE/render_check.py" --store "$STORE" "$@" ;;
   linkgraph)
     exec "$PY" "$HERE/linkgraph.py" --store "$STORE" "$@" ;;
   forget)
@@ -46,6 +48,6 @@ case "$cmd" in
     fi
     echo '{"status":"error","reason":"usage: fetch.sh forget {--label <label>|--all} (label charset: A-Za-z0-9._-)"}'
     exit 2 ;;
-  *) echo '{"status":"error","reason":"usage: fetch.sh {accounts|crux|queries|inspect|cannibal|sitemap|linkgraph|forget} [flags]"}'
+  *) echo '{"status":"error","reason":"usage: fetch.sh {accounts|crux|queries|inspect|cannibal|sitemap|rendercheck|linkgraph|forget} [flags]"}'
      exit 2 ;;
 esac