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>

account/bp/account/routes.py

@@ -1,14 +1,13 @@
 """Account pages blueprint.
 
 Moved from federation/bp/auth — newsletters, fragment pages (tickets, bookings).
-Mounted at root /.
+Mounted at root /. GET page handlers replaced by defpage.
 """
 from __future__ import annotations
 
 from quart import (
     Blueprint,
     request,
-    make_response,
     redirect,
     g,
 )
@@ -20,85 +19,62 @@ from shared.infrastructure.urls import login_url
 from shared.infrastructure.fragments import fetch_fragment, fetch_fragments
 from shared.sx.helpers import sx_response
 
-oob = {
-    "oob_extends": "oob_elements.html",
-    "extends": "_types/root/_index.html",
-    "parent_id": "root-header-child",
-    "child_id": "auth-header-child",
-    "header": "_types/auth/header/_header.html",
-    "parent_header": "_types/root/header/_header.html",
-    "nav": "_types/auth/_nav.html",
-    "main": "_types/auth/_main_panel.html",
-}
-
 
 def register(url_prefix="/"):
     account_bp = Blueprint("account", __name__, url_prefix=url_prefix)
 
-    @account_bp.context_processor
-    async def context():
+    @account_bp.before_request
+    async def _prepare_page_data():
+        """Fetch account_nav fragments and load data for defpage routes."""
+        # Fetch account nav items for layout (was in context_processor)
         events_nav, cart_nav, artdag_nav = await fetch_fragments([
             ("events", "account-nav-item", {}),
             ("cart", "account-nav-item", {}),
             ("artdag", "nav-item", {}),
         ], required=False)
-        return {"oob": oob, "account_nav": events_nav + cart_nav + artdag_nav}
+        g.account_nav = events_nav + cart_nav + artdag_nav
 
-    @account_bp.get("/")
-    async def account():
-        from shared.browser.app.utils.htmx import is_htmx_request
-        from shared.sx.page import get_template_context
-        from sx.sx_components import render_account_page, render_account_oob
+        if request.method != "GET":
+            return
 
-        if not g.get("user"):
-            return redirect(login_url("/"))
+        endpoint = request.endpoint or ""
 
-        ctx = await get_template_context()
-        if not is_htmx_request():
-            html = await render_account_page(ctx)
-            return await make_response(html)
-        else:
-            sx_src = await render_account_oob(ctx)
-            return sx_response(sx_src)
-
-    @account_bp.get("/newsletters/")
-    async def newsletters():
-        from shared.browser.app.utils.htmx import is_htmx_request
-
-        if not g.get("user"):
-            return redirect(login_url("/newsletters/"))
-
-        result = await g.s.execute(
-            select(GhostNewsletter).order_by(GhostNewsletter.name)
-        )
-        all_newsletters = result.scalars().all()
-
-        sub_result = await g.s.execute(
-            select(UserNewsletter).where(
-                UserNewsletter.user_id == g.user.id,
+        # Newsletters page — load newsletter data
+        if endpoint.endswith("defpage_newsletters"):
+            result = await g.s.execute(
+                select(GhostNewsletter).order_by(GhostNewsletter.name)
             )
-        )
-        user_subs = {un.newsletter_id: un for un in sub_result.scalars().all()}
+            all_newsletters = result.scalars().all()
 
-        newsletter_list = []
-        for nl in all_newsletters:
-            un = user_subs.get(nl.id)
-            newsletter_list.append({
-                "newsletter": nl,
-                "un": un,
-                "subscribed": un.subscribed if un else False,
-            })
+            sub_result = await g.s.execute(
+                select(UserNewsletter).where(
+                    UserNewsletter.user_id == g.user.id,
+                )
+            )
+            user_subs = {un.newsletter_id: un for un in sub_result.scalars().all()}
 
-        from shared.sx.page import get_template_context
-        from sx.sx_components import render_newsletters_page, render_newsletters_oob
+            newsletter_list = []
+            for nl in all_newsletters:
+                un = user_subs.get(nl.id)
+                newsletter_list.append({
+                    "newsletter": nl,
+                    "un": un,
+                    "subscribed": un.subscribed if un else False,
+                })
+            g.newsletters_data = newsletter_list
 
-        ctx = await get_template_context()
-        if not is_htmx_request():
-            html = await render_newsletters_page(ctx, newsletter_list)
-            return await make_response(html)
-        else:
-            sx_src = await render_newsletters_oob(ctx, newsletter_list)
-            return sx_response(sx_src)
+        # Fragment page — load fragment from events service
+        elif endpoint.endswith("defpage_fragment_page"):
+            slug = request.view_args.get("slug")
+            if slug and g.get("user"):
+                fragment_html = await fetch_fragment(
+                    "events", "account-page",
+                    params={"slug": slug, "user_id": str(g.user.id)},
+                )
+                if not fragment_html:
+                    from quart import abort
+                    abort(404)
+                g.fragment_page_data = fragment_html
 
     @account_bp.post("/newsletter/<int:newsletter_id>/toggle/")
     async def toggle_newsletter(newsletter_id: int):
@@ -128,31 +104,4 @@ def register(url_prefix="/"):
         from sx.sx_components import render_newsletter_toggle
         return sx_response(render_newsletter_toggle(un))
 
-    # Catch-all for fragment-provided pages — must be last
-    @account_bp.get("/<slug>/")
-    async def fragment_page(slug):
-        from shared.browser.app.utils.htmx import is_htmx_request
-        from quart import abort
-
-        if not g.get("user"):
-            return redirect(login_url(f"/{slug}/"))
-
-        fragment_html = await fetch_fragment(
-            "events", "account-page",
-            params={"slug": slug, "user_id": str(g.user.id)},
-        )
-        if not fragment_html:
-            abort(404)
-
-        from shared.sx.page import get_template_context
-        from sx.sx_components import render_fragment_page, render_fragment_oob
-
-        ctx = await get_template_context()
-        if not is_htmx_request():
-            html = await render_fragment_page(ctx, fragment_html)
-            return await make_response(html)
-        else:
-            sx_src = await render_fragment_oob(ctx, fragment_html)
-            return sx_response(sx_src)
-
     return account_bp