Phase 5: Page layouts as s-expressions — components, fragments, error pages

Add 9 new shared s-expression components (cart-mini, auth-menu,
account-nav-item, calendar-entry-nav, calendar-link-nav, market-link-nav,
post-card, base-shell, error-page) and wire them into all fragment route
handlers. 404/403 error pages now render entirely via s-expressions as a
full-page proof-of-concept, with Jinja fallback on failure.

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

orders/bp/fragments/routes.py

@@ -14,12 +14,11 @@ def register():
 
     async def _account_nav_item():
         from shared.infrastructure.urls import orders_url
-        href = orders_url("/")
-        return (
-            '<div class="relative nav-group">'
-            f'<a href="{href}" class="justify-center cursor-pointer flex flex-row '
-            'items-center gap-2 rounded bg-stone-200 text-black p-3" data-hx-disable>'
-            'orders</a></div>'
+        from shared.sexp.jinja_bridge import sexp as render_sexp
+
+        return render_sexp(
+            '(~account-nav-item :href href :label "orders")',
+            href=orders_url("/"),
         )
 
     _handlers = {