SubMiner/backlog/tasks/task-112 - Fix-docs-demo-video-thumbnail-cache-staleness.md

id, title, status, assignee, created_date, updated_date, labels, dependencies, priority, ordinal

id	title	status	assignee	created_date	updated_date	labels	dependencies	priority	ordinal
TASK-112	Fix docs demo video thumbnail cache staleness	Done	codex	2026-02-23 03:41	2026-02-23 03:43	bug docs media		medium	112000

Description

Docs home page demo continues to show an old thumbnail after replacing the demo video file in place. The page currently reuses static media URLs (/assets/minecard.webm, /assets/minecard.mp4, /assets/demo-poster.jpg), so browser/CDN cache can keep stale poster/video preview data.

Action Steps

1. Add a failing regression check that asserts cache-busted URL usage for docs home demo media references.
2. Update docs home demo media URLs to include a shared asset version token for poster/source/fallback paths.
3. Run the regression check and docs build validation.
4. Record fix notes and move task status to Done.

Acceptance Criteria

• #1 Docs home video references include a deterministic cache-busting token so direct asset replacement does not serve stale preview data.
• #2 Poster/source/fallback links in the demo block use the same token to avoid mixed old/new media.
• #3 Validation commands for the new regression check and docs build pass.

Implementation Notes

• Generated a fresh thumbnail from docs/public/assets/minecard.webm into docs/public/assets/minecard-poster.jpg.
• Updated docs/index.md demo block to use a shared demoAssetVersion token across poster, webm/mp4 sources, and gif fallback links.
• Follow-up: regenerated minecard-poster.jpg at exact 00:00:12 from the webm and bumped token to demoAssetVersion = '20260223-2'.
• Added regression check docs/index.assets.test.ts to ensure demo media references keep shared cache-busting URL patterns.
• Validation:
  • bun test docs/index.assets.test.ts
  • bun run docs:build