Keep image policy reactive without invalidating its consumers when only the independent hydration-complete flag changes.

Keep the native document’s React tree slots identical in Node, local capture and hydration. Empty lifecycle/console slots add no markup but preserve useId.

Native document history policy, installed before CSS and retained by BFCache.

Capture the mount’s hydration decision without subscribing its render to the later hydration-complete update. Call from a hook initializer, not derived UI.

Snapshot the mount’s entrance policy, like initial-hydration?. Completing hydration must not invalidate that mounted owner or its pending SSR children.

Track mounted pending code/data inside the page, never speculative renders. Ready and terminal error views release their blocker after the DOM commit.