Fix embedded fullscreen expand

[hugolytics]

Summary

• fullscreen the embedded viewer shell instead of the whole document
• re-run resize logic on fullscreen changes so the SVG stays visible
• add a regression test and release bump to 0.1.1

Verification

• npm test
• npm run build
• npm run docs:prepare-assets
• browser audit of embedded iframe expand/exit flow

[hugocool]

Reviewed and approved for merge.