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>

events/templates/_types/calendar/_nav.html

@@ -1,7 +1,7 @@
 <!-- Desktop nav -->
 {% import 'macros/links.html' as links %}
 {% call links.link(
-  url_for('calendar.slots.get', calendar_slug=calendar.slug),
+  url_for('calendar.slots.defpage_slots_listing', calendar_slug=calendar.slug),
   hx_select_search,
   select_colours,
   True,
@@ -14,5 +14,5 @@
 {% endcall %}
 {% if g.rights.admin %}
     {% from 'macros/admin_nav.html' import admin_nav_item %}
-    {{ admin_nav_item(url_for('calendar.admin.admin', calendar_slug=calendar.slug)) }}
+    {{ admin_nav_item(url_for('calendar.admin.defpage_calendar_admin', calendar_slug=calendar.slug)) }}
 {% endif %}

events/templates/_types/day/_row.html

@@ -23,7 +23,7 @@
       <div class="text-xs font-medium">
         {% call links.link(
           url_for(
-            'calendar.slots.slot.get',
+            'calendar.slots.slot.defpage_slot_detail',
             calendar_slug=calendar.slug,
             slot_id=entry.slot.id
           ),

events/templates/_types/markets/header/_header.html

@@ -1,7 +1,7 @@
 {% import 'macros/links.html' as links %}
 {% macro header_row(oob=False) %}
   {% call links.menu_row(id='markets-row', oob=oob) %}
-    {% call links.link(url_for('markets.home'), hx_select_search) %}
+    {% call links.link(url_for('markets.defpage_events_markets'), hx_select_search) %}
       <i class="fa fa-shopping-bag" aria-hidden="true"></i>
       <div>
         Markets

events/templates/_types/tickets/_buy_form.html

@@ -77,7 +77,7 @@
 
                   <a
                     class="relative inline-flex items-center justify-center text-emerald-700"
-                    href="{{ url_for('tickets.my_tickets') }}"
+                    href="{{ url_for('tickets.defpage_my_tickets') }}"
                   >
                     <span class="relative inline-flex items-center justify-center">
                       <i class="fa-solid fa-shopping-cart text-2xl" aria-hidden="true"></i>
@@ -166,7 +166,7 @@
 
           <a
             class="relative inline-flex items-center justify-center text-emerald-700"
-            href="{{ url_for('tickets.my_tickets') }}"
+            href="{{ url_for('tickets.defpage_my_tickets') }}"
           >
             <span class="relative inline-flex items-center justify-center">
               <i class="fa-solid fa-shopping-cart text-2xl" aria-hidden="true"></i>

events/templates/_types/tickets/_buy_result.html

@@ -14,7 +14,7 @@
   <div class="space-y-2 mb-4">
     {% for ticket in created_tickets %}
       <a
-        href="{{ url_for('tickets.ticket_detail', code=ticket.code) }}"
+        href="{{ url_for('tickets.defpage_ticket_detail', code=ticket.code) }}"
         class="flex items-center justify-between p-2 rounded-lg bg-white border border-emerald-100 hover:border-emerald-300 transition text-sm"
       >
         <div class="flex items-center gap-2">
@@ -34,7 +34,7 @@
 
   <div class="mt-3 flex gap-2">
     <a
-      href="{{ url_for('tickets.my_tickets') }}"
+      href="{{ url_for('tickets.defpage_my_tickets') }}"
       class="text-sm text-emerald-700 hover:text-emerald-900 underline"
     >
       View all my tickets

events/templates/_types/tickets/_detail_panel.html

@@ -1,7 +1,7 @@
 <section id="ticket-detail" class="{{styles.list_container}} max-w-lg mx-auto">
 
   {# Back link #}
-  <a href="{{ url_for('tickets.my_tickets') }}"
+  <a href="{{ url_for('tickets.defpage_my_tickets') }}"
      class="inline-flex items-center gap-1 text-sm text-stone-500 hover:text-stone-700 mb-4">
     <i class="fa fa-arrow-left" aria-hidden="true"></i>
     Back to my tickets

events/templates/_types/tickets/_main_panel.html

@@ -5,7 +5,7 @@
     <div class="space-y-4">
       {% for ticket in tickets %}
         <a
-          href="{{ url_for('tickets.ticket_detail', code=ticket.code) }}"
+          href="{{ url_for('tickets.defpage_ticket_detail', code=ticket.code) }}"
           class="block rounded-xl border border-stone-200 bg-white p-4 hover:shadow-md transition"
         >
           <div class="flex items-start justify-between gap-4">