[scbrown]

The playground still embeds the former GitHub Pages owner, which returns HTTP 404. Point it at intigraph.github.io and keep the section and both navigation links hidden until the HTTP probe succeeds and the expected iframe reports loading or ready within eight seconds. A loading signal reveals the explorer loader and starts one separate sixty-second deadline for ready; repeated progress cannot extend it. Remove the section on HTTP/network failure, explorer error, a silent frame, or an import that misses that sixty-second deadline. A later explorer error also removes a revealed section. JavaScript-disabled visits keep the section hidden.

The host validates both message origin and frame source, preserves bounded resize messages, and consumes quipu:state from Quipu #951, producer head c6b9a0a9f8a14ffc15bf8833595a72ee698aca40. That producer must land and deploy before live acceptance. A working, slow import remains visible after its first loading signal. Iframe load and saved preview alone do not count as that signal or as ready.

Update transferred repository links to the Intigraph organization while preserving the pinned stack-table input and its hash. Normal site CI now checks anchor, image and deferred iframe targets and fails on broken external responses or missing local files.

Validation: guarded browser checks cover ready/reveal, resize bounds, wrong origin/source, desktop/mobile stack, HTTP 404, network failure, explorer error, timeout, forged ready, error after ready, no JavaScript, an alive loader beyond eight seconds, a slow successful ready result, and finite sixty-second timeout despite repeated loading messages. All 31 unique page targets pass; the checker also rejects the measured old explorer 404. Existing namespace publication and browser tests pass. The producer's separate real-engine suite passed 30 checks, including actual import, failure/retry and parent-state messages. Guarded runs preserved 157 watched paths and two UID resources; one declared live-agent file remains outside that watch.

Demo: before 404 → after section removal, plus a ready host control and caption/screenshots. The short before/after and ready controls use explicit cross-origin response/message fixtures; the separately labelled slow-engine recording runs the actual engine. None is a deployed-site recording. All four clips played to completion in Chromium. The additional real engine recording uses two local origins and the actual released engine/pendant, with only the host fixture transport URL changed. Loading arrived at 0.35s, ready at 59.35s, and a real query returned a row. It remained visible across the eight-second boundary. These are observed timings, not a guaranteed load time. Base 239169c59b7115e3ce16f159782775c15fcd7385; candidate is pinned in this PR head and the caption's source manifest. Download WebMs if the repository viewer does not play inline.

GitHub Pages publishes main at the repository root. Rollback is a reviewed source revert followed by Pages build and served-byte verification. No deployment is claimed here.