Replace 21 Jinja render_template() calls with sx render functions

Phase 1: Wire 16 events routes to existing sx render functions
- slot, slots, ticket_types, ticket_type, calendar_entries,
  calendar_entry, calendar_entry/admin

Phase 2: Orders checkout return (2 calls)
- New orders/sx/checkout.sx with return page components
- New render_checkout_return_page() in orders/sx/sx_components.py

Phase 3: Blog menu items (3 calls)
- New blog/sx/menu_items.sx with search result components
- New render_menu_item_form() and render_page_search_results()
  in blog/sx/sx_components.py

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

blog/bp/menu_items/routes.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from quart import Blueprint, render_template, make_response, request, jsonify, g
+from quart import Blueprint, make_response, request, jsonify, g
 
 from shared.browser.app.authz import require_admin
 from .services.menu_items import (
@@ -46,11 +46,8 @@ def register():
     @require_admin
     async def new_menu_item():
         """Show form to create new menu item"""
-        html = await render_template(
-            "_types/menu_items/_form.html",
-            menu_item=None,
-        )
-        return await make_response(html)
+        from sx.sx_components import render_menu_item_form
+        return sx_response(render_menu_item_form())
 
     @bp.post("/")
     @require_admin
@@ -89,11 +86,8 @@ def register():
         if not menu_item:
             return await make_response("Menu item not found", 404)
 
-        html = await render_template(
-            "_types/menu_items/_form.html",
-            menu_item=menu_item,
-        )
-        return await make_response(html)
+        from sx.sx_components import render_menu_item_form
+        return sx_response(render_menu_item_form(menu_item=menu_item))
 
     @bp.put("/<int:item_id>/")
     @require_admin
@@ -153,14 +147,8 @@ def register():
         pages, total = await search_pages(g.s, query, page, per_page)
         has_more = (page * per_page) < total
 
-        html = await render_template(
-            "_types/menu_items/_page_search_results.html",
-            pages=pages,
-            query=query,
-            page=page,
-            has_more=has_more,
-        )
-        return await make_response(html)
+        from sx.sx_components import render_page_search_results
+        return sx_response(render_page_search_results(pages, query, page, has_more))
 
     @bp.post("/reorder/")
     @require_admin