Add sx-preserve/sx-ignore (morph skip), sx-indicator (loading element),
sx-validate (form validation), sx-boost (progressive enhancement),
sx-preload (hover prefetch with 30s cache), and sx-optimistic (instant
UI preview with rollback). Move all from HTMX_MISSING_ATTRS to
SX_UNIQUE_ATTRS with full ATTR_DETAILS docs and reference.sx demos.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
giles
31a8b755d9