Phase 7: Replace render_template() with s-expression rendering in all POST/PUT/DELETE routes

Eliminates all render_template() calls from POST/PUT/DELETE handlers across
all 7 services. Moves sexp_components.py into sexp/ packages per service.

- Blog: like toggle, snippets, cache clear, features/sumup/entry panels,
  create/delete market, WYSIWYG editor panel (render_editor_panel)
- Federation: like/unlike/boost/unboost, follow/unfollow, actor card,
  interaction buttons
- Events: ticket widget, checkin, confirm/decline/provisional, tickets
  config, posts CRUD, description edit/save, calendar/slot/ticket_type
  CRUD, payments, buy tickets, day main panel, entry page
- Market: like toggle, cart add response
- Account: newsletter toggle
- Cart: checkout error pages (3 handlers)
- Orders: checkout error page (1 handler)

Remaining render_template() calls are exclusively in GET handlers and
internal services (email templates, fragment endpoints).

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

events/bp/tickets/routes.py

@@ -51,7 +51,7 @@ def register() -> Blueprint:
         )
 
         from shared.sexp.page import get_template_context
-        from sexp_components import render_tickets_page, render_tickets_oob
+        from sexp.sexp_components import render_tickets_page, render_tickets_oob
 
         ctx = await get_template_context()
         if not is_htmx_request():
@@ -82,7 +82,7 @@ def register() -> Blueprint:
             return await make_response("Ticket not found", 404)
 
         from shared.sexp.page import get_template_context
-        from sexp_components import render_ticket_detail_page, render_ticket_detail_oob
+        from sexp.sexp_components import render_ticket_detail_page, render_ticket_detail_oob
 
         ctx = await get_template_context()
         if not is_htmx_request():
@@ -169,13 +169,20 @@ def register() -> Blueprint:
         remaining = await get_available_ticket_count(g.s, entry_id)
         all_tickets = await get_tickets_for_entry(g.s, entry_id)
 
-        html = await render_template(
-            "_types/tickets/_buy_result.html",
-            entry=entry,
-            created_tickets=created,
-            remaining=remaining,
-            all_tickets=all_tickets,
-        )
+        # Compute cart count for OOB mini-cart update
+        from shared.infrastructure.data_client import fetch_data
+        from shared.contracts.dtos import CartSummaryDTO, dto_from_dict
+        summary_params = {}
+        if ident["user_id"] is not None:
+            summary_params["user_id"] = ident["user_id"]
+        if ident["session_id"] is not None:
+            summary_params["session_id"] = ident["session_id"]
+        raw_summary = await fetch_data("cart", "cart-summary", params=summary_params, required=False)
+        summary = dto_from_dict(CartSummaryDTO, raw_summary) if raw_summary else CartSummaryDTO()
+        cart_count = summary.count + summary.calendar_count + summary.ticket_count
+
+        from sexp.sexp_components import render_buy_result
+        html = render_buy_result(entry, created, remaining, cart_count)
         return await make_response(html, 200)
 
     @bp.post("/adjust/")
@@ -298,14 +305,10 @@ def register() -> Blueprint:
         summary = dto_from_dict(CartSummaryDTO, raw_summary) if raw_summary else CartSummaryDTO()
         cart_count = summary.count + summary.calendar_count + summary.ticket_count
 
-        html = await render_template(
-            "_types/tickets/_adjust_response.html",
-            entry=entry,
-            ticket_remaining=ticket_remaining,
-            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,
+        from sexp.sexp_components import render_adjust_response
+        html = render_adjust_response(
+            entry, ticket_remaining, ticket_sold_count,
+            user_ticket_count, user_ticket_counts_by_type, cart_count,
         )
 
         return await make_response(html, 200)