sx-mount now checks if the target element has children (server-
rendered HTML). If so, skips the client re-render and only runs
hydration (process-elements, hydrate-islands, hydrate-elements).
This preserves server-rendered CSSX styling and avoids the flash
of unstyled content that occurred when the client replaced the
server HTML before re-rendering.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
giles
8f2a51af9d