fix(catalog): restore the caption texture preview

[AksharP5]

What

The Caption Texture catalog page currently plays a blank preview. This restores the textured caption animation.

Fixes #3257.

Why

The catalog publishes the texture beside the component payload, but the demo requests the install-only compositions/components/lava.png path. That request returns 404, and the missing CSS mask makes every caption word invisible.

How

Pointed the demo at the source-relative texture filename and regenerated the catalog payload. The installable component still uses its existing nested asset path.

Test plan

• Unit tests added/updated
• Manual testing performed
• Documentation updated (generated catalog payload)

Validated with:

• bun run build
• bun run lint:registry-items caption-texture
• bunx oxfmt --check registry/components/caption-texture/demo.html docs/public/catalog/components/caption-texture.json
• npx hyperframes check against the standalone demo and its flat catalog assets
• Browser playback against the generated catalog payload, with zero failed network responses after the fix

Before and after

comparison.mp4