Wire island hydration into post-swap lifecycle

- orchestration.sx: post-swap calls sx-hydrate-islands for new islands
  in swapped content, plus process-emit-elements for data-sx-emit
- Regenerate sx-ref.js

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

shared/sx/ref/orchestration.sx

@@ -432,6 +432,7 @@
     (activate-scripts root)
     (sx-process-scripts root)
     (sx-hydrate root)
+    (sx-hydrate-islands root)
     (process-elements root)))