Refresh the free-tier demo and floating preview

[sergei-argutin]

What changed

• refresh the vendored 400-exercise free bundle and generated static image map
• add the missing react-native-web dependency for clean web installs
• replace the buried paid preview with a compact floating overlay that remains visible while scrolling
• cap detail artwork on wide screens and remove the default index Stack title
• exclude paid start/peak stills from the looping-animation gallery

Why

The web example depended on an unrecorded local package, oversized detail artwork dominated desktop screens, and the paid-tier preview disappeared as part of the long exercise list.

Validation

• npm run gen-images: 741 flat images, 1 sample animation, 27 muscle icons, 46 equipment icons
• npm run typecheck
• local browser verification before and after scrolling confirmed the overlay remains fixed

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Keep the floating preview above the bottom safe area

On devices with a nonzero bottom inset, such as gesture-navigation iPhones and edge-to-edge Android devices, the surrounding SafeAreaView explicitly excludes the bottom edge, so positioning this card at bottom: 16 places part of it inside the home-indicator/navigation area. Offset the overlay using the bottom safe-area inset (and account for the resulting height in the list padding) so the preview remains fully visible and usable.

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