Replace tagline with the sx identity cycle

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

sx/sxc/home.sx

@@ -9,8 +9,7 @@
     (p :class "text-sm text-stone-400"
       "© Giles Bradshaw 2026")
     (p :class "text-lg text-stone-500 max-w-2xl mx-auto mb-12"
-      "A hypermedia-driven UI engine that combines htmx's server-first philosophy "
-      "with React's component model. S-expressions over the wire — no HTML, no JavaScript frameworks.")
+      "(sx === code === data === protocol === content === behaviour === layout === style === spec === sx)")
     (div :class "bg-stone-100 rounded-lg p-6 text-left font-mono text-sm mx-auto max-w-2xl"
       (pre :class "leading-relaxed whitespace-pre-wrap" children))))