Docs: refresh dashboard images for the edge-lit icon tiles

[SandObserver]

Summary

• Recapture the landing hero from a DEMO_MODE build of app main with the edge-lit icon tile finish, same layout, badges and Now Playing session as before.
• Recomposite the Open Graph image with a fresh dashboard capture in the same device frame.
• Rename both files by content hash and update the references in astro.config.mjs, src/pages/index.astro and docs/index.md.
• Run sync-widgets against app main, which also brings in limits.js and the updated admin scripts.

Testing
npm run build and npm run check pass. Images captured in headless Chromium with SF Pro Text, dark wallpaper only.

Checklist

• npm run build and npm run check both pass.
• Product UI is shown by running or capturing it, never recreated in CSS.
• Any new preview or screenshot carries no private hostnames or real data.
• Visual changes verified in both colour schemes and both docs themes.
• Links to the app repo still resolve.

[cloudflare-workers-and-pages]

Deploying stackyard-docs with    Cloudflare Pages

Latest commit:	84ff917
Status:	✅  Deploy successful!
Preview URL:	https://11f1fe52.stackyard-docs.pages.dev
Branch Preview URL:	https://docs-icon-tile-finish-screen.stackyard-docs.pages.dev

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