Migrate all apps to defpage declarative page routes

Replace Python GET page handlers with declarative defpage definitions in .sx
files across all 8 apps (sx docs, orders, account, market, cart, federation,
events, blog). Each app now has sxc/pages/ with setup functions, layout
registrations, page helpers, and .sx defpage declarations.

Core infrastructure: add g I/O primitive, PageDef support for auth/layout/
data/content/filter/aside/menu slots, post_author auth level, and custom
layout registration. Remove ~1400 lines of render_*_page/render_*_oob
boilerplate. Update all endpoint references in routes, sx_components, and
templates to defpage_* naming.

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

orders/bp/order/routes.py

@@ -2,16 +2,13 @@ from __future__ import annotations
 
 from quart import Blueprint, g, redirect, url_for, make_response
 from sqlalchemy import select
-from sqlalchemy.orm import selectinload
 
 from shared.models.order import Order
 from shared.browser.app.payments.sumup import create_checkout as sumup_create_checkout
 from shared.config import config
 
 from shared.infrastructure.cart_identity import current_cart_identity
-from shared.sx.page import get_template_context
 from services.check_sumup_status import check_sumup_status
-from shared.browser.app.utils.htmx import is_htmx_request
 
 from .filters.qs import makeqs_factory, decode
 
@@ -33,34 +30,6 @@ def register() -> Blueprint:
     def route():
         g.makeqs_factory = makeqs_factory
 
-    @bp.get("/")
-    async def order_detail(order_id: int):
-        """Show a single order + items."""
-        owner = _owner_filter()
-        if owner is None:
-            return await make_response("Order not found", 404)
-        result = await g.s.execute(
-            select(Order)
-            .options(selectinload(Order.items))
-            .where(Order.id == order_id, owner)
-        )
-        order = result.scalar_one_or_none()
-        if not order:
-            return await make_response("Order not found", 404)
-
-        from sx.sx_components import render_order_page, render_order_oob
-
-        ctx = await get_template_context()
-        calendar_entries = ctx.get("calendar_entries")
-
-        if not is_htmx_request():
-            html = await render_order_page(ctx, order, calendar_entries, url_for)
-            return await make_response(html)
-        else:
-            from shared.sx.helpers import sx_response
-            sx_src = await render_order_oob(ctx, order, calendar_entries, url_for)
-            return sx_response(sx_src)
-
     @bp.get("/pay/")
     async def order_pay(order_id: int):
         """Re-open the SumUp payment page for this order."""
@@ -73,7 +42,7 @@ def register() -> Blueprint:
             return await make_response("Order not found", 404)
 
         if order.status == "paid":
-            return redirect(url_for("orders.order.order_detail", order_id=order.id))
+            return redirect(url_for("orders.defpage_order_detail", order_id=order.id))
 
         if order.sumup_hosted_url:
             return redirect(order.sumup_hosted_url)
@@ -120,13 +89,13 @@ def register() -> Blueprint:
             return await make_response("Order not found", 404)
 
         if not order.sumup_checkout_id:
-            return redirect(url_for("orders.order.order_detail", order_id=order.id))
+            return redirect(url_for("orders.defpage_order_detail", order_id=order.id))
 
         try:
             await check_sumup_status(g.s, order)
         except Exception:
             pass
 
-        return redirect(url_for("orders.order.order_detail", order_id=order.id))
+        return redirect(url_for("orders.defpage_order_detail", order_id=order.id))
 
     return bp