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>

blog/bp/post/routes.py

@@ -21,6 +21,7 @@ from shared.browser.app.redis_cacher import cache_page, clear_cache
 from .admin.routes import register as register_admin
 from shared.config import config
 from shared.browser.app.utils.htmx import is_htmx_request
+from shared.sexp.helpers import sexp_response
 
 def register():
   bp = Blueprint("post", __name__, url_prefix='/<slug>')
@@ -70,7 +71,7 @@ def register():
           post_slug = (g.post_data.get("post") or {}).get("slug", "")
 
           # Fetch container nav from relations service
-          container_nav_html = await fetch_fragment("relations", "container-nav", params={
+          container_nav = await fetch_fragment("relations", "container-nav", params={
               "container_type": "page",
               "container_id": str(db_post_id),
               "post_slug": post_slug,
@@ -79,7 +80,7 @@ def register():
           ctx = {
               **p_data,
               "base_title": config()["title"],
-              "container_nav_html": container_nav_html,
+              "container_nav": container_nav,
           }
 
           # Page cart badge via HTTP
@@ -109,10 +110,10 @@ def register():
     tctx = await get_template_context()
     if not is_htmx_request():
         html = await render_post_page(tctx)
+        return await make_response(html)
     else:
-        html = await render_post_oob(tctx)
-
-    return await make_response(html)
+        sexp_src = await render_post_oob(tctx)
+        return sexp_response(sexp_src)
 
   @bp.post("/like/toggle/")
   @clear_cache(tag="post.post_detail", tag_scope="user")
@@ -124,9 +125,7 @@ def register():
 
       # Get post_id from g.post_data
       if not g.user:
-          html = render_like_toggle_button(slug, False, like_url)
-          resp = make_response(html, 403)
-          return resp
+          return sexp_response(render_like_toggle_button(slug, False, like_url), status=403)
 
       post_id = g.post_data["post"]["id"]
       user_id = g.user.id
@@ -136,8 +135,7 @@ def register():
       })
       liked = result["liked"]
 
-      html = render_like_toggle_button(slug, liked, like_url)
-      return html
+      return sexp_response(render_like_toggle_button(slug, liked, like_url))
 
   @bp.get("/w/<widget_domain>/")
   async def widget_paginate(slug: str, widget_domain: str):