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/page_markets/routes.py

@@ -12,6 +12,7 @@ from __future__ import annotations
 from quart import Blueprint, g, request, render_template, make_response
 
 from shared.browser.app.utils.htmx import is_htmx_request
+from shared.sexp.helpers import sexp_response
 from shared.services.registry import services
 
 
@@ -45,11 +46,11 @@ def register() -> Blueprint:
         tctx = await get_template_context()
         tctx["post"] = post
         if is_htmx_request():
-            html = await render_page_markets_oob(tctx, markets, has_more, page)
+            sexp_src = await render_page_markets_oob(tctx, markets, has_more, page)
+            return sexp_response(sexp_src)
         else:
             html = await render_page_markets_page(tctx, markets, has_more, page)
-
-        return await make_response(html, 200)
+            return await make_response(html, 200)
 
     @bp.get("/page-markets")
     async def markets_fragment():
@@ -60,7 +61,7 @@ def register() -> Blueprint:
 
         from sexp.sexp_components import render_page_markets_cards
         post_slug = post.get("slug", "")
-        html = await render_page_markets_cards(markets, has_more, page, post_slug)
-        return await make_response(html, 200)
+        sexp_src = await render_page_markets_cards(markets, has_more, page, post_slug)
+        return sexp_response(sexp_src)
 
     return bp