Expand prefetch plan: full strategy spectrum and components+data split
Add prefetch strategies section covering the full timing spectrum:
eager bundle (initial load), idle timer (requestIdleCallback), viewport
(IntersectionObserver), mouse trajectory prediction, hover, mousedown,
and the components+data hybrid for :data pages. Add declarative
configuration via defpage :prefetch metadata and sx-prefetch attributes.
Update rollout to 7 incremental steps.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
giles
e38534a898