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>

events/bp/calendar_entry/admin/routes.py

@@ -1,28 +1,29 @@
 from __future__ import annotations
 
 from quart import (
-    render_template, make_response, Blueprint
+    make_response, Blueprint
 )
 
-
 from shared.browser.app.authz import require_admin
+from shared.browser.app.utils.htmx import is_htmx_request
+from shared.sx.helpers import sx_response
 
 
 def register():
     bp = Blueprint("admin", __name__, url_prefix='/admin')
-    
+
     # ---------- Pages ----------
     @bp.get("/")
     @require_admin
     async def admin(entry_id: int, **kwargs):
-        from shared.browser.app.utils.htmx import is_htmx_request
+        from shared.sx.page import get_template_context
+        from sx.sx_components import render_entry_admin_page, render_entry_admin_oob
 
-        # Determine which template to use based on request type
+        tctx = await get_template_context()
         if not is_htmx_request():
-            # Normal browser request: full page with layout
-            html = await render_template("_types/entry/admin/index.html")
+            html = await render_entry_admin_page(tctx)
+            return await make_response(html)
         else:
-            html = await render_template("_types/entry/admin/_oob_elements.html")
-
-        return await make_response(html)
+            sx_src = await render_entry_admin_oob(tctx)
+            return sx_response(sx_src)
     return bp