Fix SPA navigation breaking custom element initialization
Two bugs in navigateTo() prevented x-ocaml cells from working after
SPA sidebar navigation:
1. innerHTML assignment — replaced with document.adoptNode() + appendChild
so custom elements get properly connected and connectedCallback fires
2. Script cloneNode — cloned script elements are marked "parser-inserted"
and browsers refuse to execute them. Use document.createElement('script')
instead to create fresh executable script elements.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>