# ECP-0123: Instant Station Guide and Player Warmup

Status: Draft

## Problem statement

The hosted watch page can feel broken when `/api/public-streams` is slow, empty, or temporarily
unreachable: the channel rail waits on the network before showing stations. Even after stations
appear, the first channel tap pays the `@moq/watch` module import cost before the player element can
mount. That increases time to first playing frame and makes channel selection feel unreliable.

## Constraints

- Keep the first screen a usable TV/player interface, not a marketing page.
- Preserve manual tuning, share links, DVR mode, public station refresh, and existing relay fields.
- Keep rollback simple: the live API remains authoritative after it answers.
- Avoid Chrome-only transport assumptions and keep live playback failure messages actionable.
- Keep the change static-site compatible so Cloudflare Worker asset deployment stays simple.

## Decision

Embed the current starter LA station guide in `index.html` and render it immediately on first load.
Also keep a short-lived local guide cache, merge cached entries with the HTML seed, and refresh
`/api/public-streams` in the background with a bounded timeout. A slow or empty refresh no longer
clears already visible channels.

Change the web client, publisher module defaults, runbook examples, and remote watch E2E default
relay to `https://relay.every.channel/anon`. Preload/preconnect the primary player dependencies and
warm the `@moq/watch` custom element after first paint. Let `@moq/watch` use its available live
transport fallback instead of forcing WebTransport-only playback. Add client performance marks for
guide first render, guide fetch, watch request, player module readiness, player mount, catalog/live
status, and first observable canvas frame when the browser exposes it.

## Alternatives considered

- Wait only for `/api/public-streams`. Rejected because the UI becomes blank when the directory is
  slow and because children should be able to tap visible channels immediately.
- Make the API response cacheable at the CDN. Rejected as the only fix because active streams are
  short TTL and stale-but-visible fallback belongs in the client.
- Bundle `@moq/watch` into the static site. Deferred because CDN import fallback is already in use;
  warming and modulepreload reduce tap latency without changing the build graph.

## Rollout / teardown plan

Ship the static web change with the existing Worker asset deploy. Validate with clean-cache
desktop/mobile browser loads and check the app's `window.__ecPerf` marks. Teardown is removing the
HTML seed/cache/warmup path and returning to live-API-only station rendering.