Store IGDB data and refresh it after the response

[engleek]

Goal

Store each game's IGDB data in the database and refresh it in the background, instead of calling IGDB live on every game page. This picks up #112's design (background IGDB fetching), adapted to Cloudflare Workers (ADR 0002, #253).

Today

• app/models/game.js calls getIGDBGame(game.igdb_slug) on every game page view, so each view makes 1–2 outside requests (the Twitch token, then IGDB).
• app/utils/igdb.server.js caches the Twitch token with memory-cache, in process memory. On Workers that memory doesn't last between requests.
• The slug is interpolated into the Apicalypse query (where slug = "${slug}") without escaping.
• 213 games have an igdb_slug (production, 2026-10-04).

Design

• Columns on game: igdb_data (JSON) and igdb_data_fetched_at.
• Read path: the game page uses the stored igdb_data. If it's missing or older than a day, the refresh runs after the response (ctx.waitUntil on Workers; fire-and-forget on Node until then). The page never waits for IGDB. The only exception is a game whose slug was just set and has no data yet: show it without the IGDB section, then show it on the next view.
• Avoid duplicate refreshes: set an igdb_refresh_started_at before fetching, and skip if it's under ~10 minutes old.
• Cron: a scheduled job (a Cron Trigger on Workers) refreshes the stalest N games, so data stays fresh for games nobody visits. Keep N small enough for the free plan's limits.
• Twitch token: store it with its expiry in a kv_store-style table (or KV), and refresh it shortly before it expires.
• On slug change (create or edit): clear igdb_data, so the old game's data never shows.
• No pgmq, no node-cron, no igdb-api-node: call the IGDB API with fetch and an escaped query.

Acceptance criteria

• A game page view makes no request to IGDB or Twitch while its stored data is fresh.
• Stale data is served immediately and refreshed after the response; two concurrent views start at most one refresh.
• Changing a game's IGDB slug clears its data, and the next refresh fetches the new game.
• A slug containing " can't change the IGDB query.
• Unit tests cover staleness, the refresh guard, token expiry and query escaping. An e2e test runs against a local IGDB stand-in (like the Discord and Bluesky ones in playwright.config.js).
• igdb-api-node and memory-cache are removed.

Notes

• This can land before the cutover, on Node: the refresh runs after the response there too, and the cron becomes a small script until Workers.
• Supersedes feat: Asynchronous IGDB data fetching #112.