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>

events/sexp/payments.sexpr

@@ -6,7 +6,7 @@
       (h3 :class "text-lg font-semibold text-stone-800"
         (i :class "fa fa-credit-card text-purple-600 mr-1") " SumUp Payment")
       (p :class "text-xs text-stone-400" "Configure per-page SumUp credentials. Leave blank to use the global merchant account.")
-      (form :hx-put update-url :hx-target "#payments-panel" :hx-swap "outerHTML" :hx-select "#payments-panel" :class "space-y-3"
+      (form :sx-put update-url :sx-target "#payments-panel" :sx-swap "outerHTML" :sx-select "#payments-panel" :class "space-y-3"
         (input :type "hidden" :name "csrf_token" :value csrf)
         (div (label :class "block text-xs font-medium text-stone-600 mb-1" "Merchant Code")
           (input :type "text" :name "merchant_code" :value merchant-code :placeholder "e.g. ME4J6100" :class input-cls))
@@ -23,10 +23,10 @@
 (defcomp ~events-markets-create-form (&key create-url csrf)
   (<>
     (div :id "market-create-errors" :class "mt-2 text-sm text-red-600")
-    (form :class "mt-4 flex gap-2 items-end" :hx-post create-url
-          :hx-target "#markets-list" :hx-select "#markets-list" :hx-swap "outerHTML"
-          :hx-on::before-request "document.querySelector('#market-create-errors').textContent='';"
-          :hx-on::response-error "document.querySelector('#market-create-errors').innerHTML = event.detail.xhr.responseText;"
+    (form :class "mt-4 flex gap-2 items-end" :sx-post create-url
+          :sx-target "#markets-list" :sx-select "#markets-list" :sx-swap "outerHTML"
+          :sx-on:beforeRequest "document.querySelector('#market-create-errors').textContent='';"
+          :sx-on:responseError "document.querySelector('#market-create-errors').textContent='Error'; if(event.detail.response){event.detail.response.clone().text().then(function(t){event.target.closest('form').querySelector('[id$=errors]').innerHTML=t})}"
       (input :type "hidden" :name "csrf_token" :value csrf)
       (div :class "flex-1"
         (label :class "block text-sm text-gray-600" "Name")
@@ -34,10 +34,10 @@
                :placeholder "e.g. Farm Shop, Bakery"))
       (button :type "submit" :class "border rounded px-3 py-2" "Add market"))))
 
-(defcomp ~events-markets-panel (&key form-html list-html)
+(defcomp ~events-markets-panel (&key form list)
   (section :class "p-4"
-    (raw! form-html)
-    (div :id "markets-list" :class "mt-6" (raw! list-html))))
+    form
+    (div :id "markets-list" :class "mt-6" list)))
 
 (defcomp ~events-markets-empty ()
   (p :class "text-gray-500 mt-4" "No markets yet. Create one above."))
@@ -53,7 +53,7 @@
               :data-confirm-text "Products will be hidden (soft delete)"
               :data-confirm-icon "warning" :data-confirm-confirm-text "Yes, delete it"
               :data-confirm-cancel-text "Cancel" :data-confirm-event "confirmed"
-              :hx-delete del-url :hx-trigger "confirmed"
-              :hx-target "#markets-list" :hx-select "#markets-list" :hx-swap "outerHTML"
-              :hx-headers csrf-hdr
+              :sx-delete del-url :sx-trigger "confirmed"
+              :sx-target "#markets-list" :sx-select "#markets-list" :sx-swap "outerHTML"
+              :sx-headers csrf-hdr
         (i :class "fa-solid fa-trash")))))