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_entries/routes.py

@@ -265,18 +265,27 @@ def register():
     
     @bp.get("/add/")
     async def add_form(day: int, month: int, year: int, **kwargs):
-        html = await render_template(
-            "_types/day/_add.html",
-        )
-        return await make_response(html)
-    
+        from datetime import date as date_cls
+        from sqlalchemy import select as sa_select
+        from models.calendars import CalendarSlot as _CS
+
+        day_date = date_cls(year, month, day)
+        weekday_attr = ["mon","tue","wed","thu","fri","sat","sun"][day_date.weekday()]
+        stmt = sa_select(_CS).where(
+            _CS.calendar_id == g.calendar.id,
+            getattr(_CS, weekday_attr) == True,
+            _CS.deleted_at.is_(None),
+        ).order_by(_CS.time_start.asc(), _CS.id.asc())
+        result = await g.s.execute(stmt)
+        day_slots = list(result.scalars())
+
+        from sx.sx_components import render_entry_add_form
+        return sx_response(render_entry_add_form(g.calendar, day, month, year, day_slots))
+
     @bp.get("/add-button/")
     async def add_button(day: int, month: int, year: int, **kwargs):
-        
-        html = await render_template(
-            "_types/day/_add_button.html",
-        )
-        return await make_response(html)
+        from sx.sx_components import render_entry_add_button
+        return sx_response(render_entry_add_button(g.calendar, day, month, year))