Improve: animate the landing page header logo on hover

[SandObserver]

Summary

• Replace the header wordmark image with an inline SVG mark and the name as text, matching the Posteryard header.
• Turn the arc once around the mark when the pointer enters the logo; the arc passes behind the Y as if behind a cube edge.
• Skip the motion for touch taps and when reduced motion is on; a running turn is never restarted.
• Below 375 px the name is visually hidden and stays available to screen readers.

Testing

npm run build and npm run check pass. Chrome checks for hover, rapid hover, touch taps, reduced motion, resize mid-play and header layout from 320 to 1440 px all pass. The landing page has one colour scheme; docs pages are unchanged.

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]

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