Send all responses as sexp wire format with client-side rendering

- Server sends sexp source text, client (sexp.js) renders everything
- SexpExpr marker class for nested sexp composition in serialize()
- sexp_page() HTML shell with data-mount="body" for full page loads
- sexp_response() returns text/sexp for OOB/partial responses
- ~app-body layout component replaces ~app-layout (no raw!)
- ~rich-text is the only component using raw! (for CMS HTML content)
- Fragment endpoints return text/sexp, auto-wrapped in SexpExpr
- All _*_html() helpers converted to _*_sexp() returning sexp source
- Head auto-hoist: sexp.js moves meta/title/link/script[ld+json]
  from rendered body to document.head automatically
- Unknown components render warning box instead of crashing page
- Component kwargs preserve AST for lazy rendering (fixes <> in kwargs)
- Fix unterminated paren in events/sexp/tickets.sexpr

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

shared/browser/templates/social/search.html

@@ -6,9 +6,9 @@
 <h1 class="text-2xl font-bold mb-6">Search</h1>
 
 <form method="get" action="{{ url_for('ap_social.search') }}" class="mb-6"
-      hx-get="{{ url_for('ap_social.search_page') }}"
-      hx-target="#search-results"
-      hx-push-url="{{ url_for('ap_social.search') }}">
+      sx-get="{{ url_for('ap_social.search_page') }}"
+      sx-target="#search-results"
+      sx-push-url="{{ url_for('ap_social.search') }}">
   <div class="flex gap-2">
     <input type="text" name="q" value="{{ query }}"
       class="flex-1 border border-stone-300 rounded-lg px-4 py-2 focus:outline-none focus:ring-2 focus:ring-stone-500"