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>

market/bp/fragments/routes.py

@@ -1,6 +1,6 @@
 """Market app fragment endpoints.
 
-Exposes HTML fragments at ``/internal/fragments/<type>`` for consumption
+Exposes sexp fragments at ``/internal/fragments/<type>`` for consumption
 by other coop apps via the fragment client.
 """
 
@@ -26,16 +26,16 @@ def register():
     async def get_fragment(fragment_type: str):
         handler = _handlers.get(fragment_type)
         if handler is None:
-            return Response("", status=200, content_type="text/html")
-        html = await handler()
-        return Response(html, status=200, content_type="text/html")
+            return Response("", status=200, content_type="text/sexp")
+        src = await handler()
+        return Response(src, status=200, content_type="text/sexp")
 
     # --- container-nav fragment: market links --------------------------------
 
     async def _container_nav_handler():
         from quart import current_app
         from shared.infrastructure.urls import market_url
-        from shared.sexp.jinja_bridge import render as render_comp
+        from shared.sexp.helpers import sexp_call
 
         container_type = request.args.get("container_type", "page")
         container_id = int(request.args.get("container_id", 0))
@@ -51,21 +51,31 @@ def register():
         parts = []
         for m in markets:
             href = market_url(f"/{post_slug}/{m.slug}/")
-            parts.append(render_comp(
-                "market-link-nav",
-                href=href, name=m.name, nav_class=nav_class,
-            ))
-        return "\n".join(parts)
+            parts.append(sexp_call("market-link-nav",
+                                   href=href, name=m.name, nav_class=nav_class))
+        return "(<> " + " ".join(parts) + ")"
 
     _handlers["container-nav"] = _container_nav_handler
 
     # --- link-card fragment: product preview card --------------------------------
 
+    def _product_link_card_sexp(product, link: str) -> str:
+        from shared.sexp.helpers import sexp_call
+        subtitle = product.brand or ""
+        detail = ""
+        if product.special_price:
+            detail = f"{product.regular_price} → {product.special_price}"
+        elif product.regular_price:
+            detail = str(product.regular_price)
+        return sexp_call("link-card",
+                         title=product.title, image=product.image,
+                         subtitle=subtitle, detail=detail,
+                         link=link)
+
     async def _link_card_handler():
         from sqlalchemy import select
         from shared.models.market import Product
         from shared.infrastructure.urls import market_url
-        from shared.sexp.jinja_bridge import render as render_comp
 
         slug = request.args.get("slug", "")
         keys_raw = request.args.get("keys", "")
@@ -80,18 +90,8 @@ def register():
                     await g.s.execute(select(Product).where(Product.slug == s))
                 ).scalar_one_or_none()
                 if product:
-                    subtitle = product.brand or ""
-                    detail = ""
-                    if product.special_price:
-                        detail = f"<s>{product.regular_price}</s> {product.special_price}"
-                    elif product.regular_price:
-                        detail = str(product.regular_price)
-                    parts.append(render_comp(
-                        "link-card",
-                        title=product.title, image=product.image,
-                        subtitle=subtitle, detail=detail,
-                        link=market_url(f"/product/{product.slug}/"),
-                    ))
+                    parts.append(_product_link_card_sexp(
+                        product, market_url(f"/product/{product.slug}/")))
             return "\n".join(parts)
 
         # Single mode
@@ -102,18 +102,7 @@ def register():
         ).scalar_one_or_none()
         if not product:
             return ""
-        subtitle = product.brand or ""
-        detail = ""
-        if product.special_price:
-            detail = f"<s>{product.regular_price}</s> {product.special_price}"
-        elif product.regular_price:
-            detail = str(product.regular_price)
-        return render_comp(
-            "link-card",
-            title=product.title, image=product.image,
-            subtitle=subtitle, detail=detail,
-            link=market_url(f"/product/{product.slug}/"),
-        )
+        return _product_link_card_sexp(product, market_url(f"/product/{product.slug}/"))
 
     _handlers["link-card"] = _link_card_handler