Replace widget registry with fragment fetches (Phase 5)

Account nav and page panels now fetched from events/cart fragments
instead of using shared widget registry.

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

bp/account/routes.py

@@ -1,6 +1,6 @@
 """Account pages blueprint.
 
-Moved from federation/bp/auth — newsletters, widget pages (tickets, bookings).
+Moved from federation/bp/auth — newsletters, fragment pages (tickets, bookings).
 Mounted at root /.
 """
 from __future__ import annotations
@@ -17,8 +17,8 @@ from sqlalchemy import select
 
 from shared.models import UserNewsletter
 from shared.models.ghost_membership_entities import GhostNewsletter
-from shared.services.widget_registry import widgets
 from shared.infrastructure.urls import login_url
+from shared.infrastructure.fragments import fetch_fragment, fetch_fragments
 
 oob = {
     "oob_extends": "oob_elements.html",
@@ -36,8 +36,12 @@ def register(url_prefix="/"):
     account_bp = Blueprint("account", __name__, url_prefix=url_prefix)
 
     @account_bp.context_processor
-    def context():
-        return {"oob": oob, "account_nav_links": widgets.account_nav}
+    async def context():
+        events_nav, cart_nav = await fetch_fragments([
+            ("events", "account-nav-item", {}),
+            ("cart", "account-nav-item", {}),
+        ])
+        return {"oob": oob, "account_nav_html": events_nav + cart_nav}
 
     @account_bp.get("/")
     async def account():
@@ -128,33 +132,35 @@ def register(url_prefix="/"):
             un=un,
         )
 
-    # Catch-all for widget pages — must be last
+    # Catch-all for fragment-provided pages — must be last
     @account_bp.get("/<slug>/")
-    async def widget_page(slug):
+    async def fragment_page(slug):
         from shared.browser.app.utils.htmx import is_htmx_request
         from quart import abort
 
-        widget = widgets.account_page_by_slug(slug)
-        if not widget:
-            abort(404)
-
         if not g.get("user"):
             return redirect(login_url(f"/{slug}/"))
 
-        ctx = await widget.context_fn(g.s, user_id=g.user.id)
-        w_oob = {**oob, "main": widget.template}
+        fragment_html = await fetch_fragment(
+            "events", "account-page",
+            params={"slug": slug, "user_id": str(g.user.id)},
+        )
+        if not fragment_html:
+            abort(404)
+
+        w_oob = {**oob, "main": "_types/auth/_fragment_panel.html"}
 
         if not is_htmx_request():
             html = await render_template(
                 "_types/auth/index.html",
                 oob=w_oob,
-                **ctx,
+                page_fragment_html=fragment_html,
             )
         else:
             html = await render_template(
                 "_types/auth/_oob_elements.html",
                 oob=w_oob,
-                **ctx,
+                page_fragment_html=fragment_html,
             )
 
         return await make_response(html)