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/menu_items/routes.py

@@ -13,6 +13,7 @@ from .services.menu_items import (
     MenuItemError,
 )
 from shared.browser.app.utils.htmx import is_htmx_request
+from shared.sexp.helpers import sexp_response
 
 def register():
     bp = Blueprint("menu_items", __name__, url_prefix='/settings/menu_items')
@@ -36,10 +37,10 @@ def register():
         tctx["menu_items"] = menu_items
         if not is_htmx_request():
             html = await render_menu_items_page(tctx)
+            return await make_response(html)
         else:
-            html = await render_menu_items_oob(tctx)
-
-        return await make_response(html)
+            sexp_src = await render_menu_items_oob(tctx)
+            return sexp_response(sexp_src)
 
     @bp.get("/new/")
     @require_admin
@@ -75,7 +76,7 @@ def register():
             from sexp.sexp_components import render_menu_items_list
             html = render_menu_items_list(menu_items)
             nav_oob = get_menu_items_nav_oob_sync(menu_items)
-            return await make_response(html + nav_oob, 200)
+            return sexp_response(html + nav_oob)
 
         except MenuItemError as e:
             return jsonify({"message": str(e), "errors": {}}), 400
@@ -118,7 +119,7 @@ def register():
             from sexp.sexp_components import render_menu_items_list
             html = render_menu_items_list(menu_items)
             nav_oob = get_menu_items_nav_oob_sync(menu_items)
-            return await make_response(html + nav_oob, 200)
+            return sexp_response(html + nav_oob)
 
         except MenuItemError as e:
             return jsonify({"message": str(e), "errors": {}}), 400
@@ -139,7 +140,7 @@ def register():
         from sexp.sexp_components import render_menu_items_list
         html = render_menu_items_list(menu_items)
         nav_oob = get_menu_items_nav_oob_sync(menu_items)
-        return await make_response(html + nav_oob, 200)
+        return sexp_response(html + nav_oob)
 
     @bp.get("/pages/search/")
     @require_admin
@@ -186,6 +187,6 @@ def register():
         from sexp.sexp_components import render_menu_items_list
         html = render_menu_items_list(menu_items)
         nav_oob = get_menu_items_nav_oob_sync(menu_items)
-        return await make_response(html + nav_oob, 200)
+        return sexp_response(html + nav_oob)
 
     return bp