Complete representative host-application acceptance #8

The current effect engine supports current-document HTML and child insertion/resize refresh. Filters create containing blocks; Shadow DOM/iframe interiors and attribute-only font/style refresh are documented boundaries.

• Exercise sticky/fixed overlays, forms, route navigation, dynamic content and late font loading in representative hosts.
• Verify simultaneous features, close/reopen, reload, blocked/corrupt storage, reset and provider removal.
• Verify custom-feature restore/reset/cleanup and removed-control behavior.
• Confirm media hiding retains layout and document that playback continues.
• Record known host limitations and fix any P0 defect; do not silently broaden compatibility claims.

Acceptance: application-level results and no known critical host regression within the advertised contract.

References: roadmap, development/acceptance guide.