Fix cart-mini OOB: compute cart_count explicitly in adjust route

Pass cart_count directly to the template instead of relying on the
context processor, which may not resolve correctly for the /tickets/
URL prefix.

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

bp/tickets/routes.py

@@ -286,6 +286,13 @@ def register() -> Blueprint:
                         ticket_type_id=tt.id,
                     )
 
+        # Compute cart count for OOB mini-cart update
+        from shared.services.registry import services
+        summary = await services.cart.cart_summary(
+            g.s, user_id=ident["user_id"], session_id=ident["session_id"],
+        )
+        cart_count = summary.count + summary.calendar_count + summary.ticket_count
+
         html = await render_template(
             "_types/tickets/_adjust_response.html",
             entry=entry,
@@ -293,6 +300,7 @@ def register() -> Blueprint:
             ticket_sold_count=ticket_sold_count,
             user_ticket_count=user_ticket_count,
             user_ticket_counts_by_type=user_ticket_counts_by_type,
+            cart_count=cart_count,
         )
 
         return await make_response(html, 200)

templates/_types/tickets/_adjust_response.html

@@ -1,2 +1,4 @@
-{# Response for ticket adjust — re-render the buy form #}
+{# Response for ticket adjust — buy form + OOB cart-mini update #}
+{% from '_types/cart/_mini.html' import mini %}
+{{ mini(oob='true') }}
 {% include '_types/tickets/_buy_form.html' %}