Delete account/sx/sx_components.py — all rendering now in .sx

Phase 1 of zero-Python rendering: account service.

- Auth pages (login, device, check-email) use _render_auth_page() helper
  calling render_to_sx() + full_page_sx() directly in routes
- Newsletter toggle POST renders inline via render_to_sx()
- Newsletter page helper returns data dict; defpage :data slot fetches,
  :content slot renders via ~account-newsletters-content defcomp
- Fragment page uses (frag ...) IO primitive directly in .sx
- Defpage _eval_slot now uses async_eval_slot_to_sx which expands
  component bodies server-side (executing IO) but serializes tags as SX
- Fix pre-existing OOB ParseError: _eval_slot was producing HTML instead
  of s-expressions for component content slots
- Fix market url_for endpoint: defpage_market_home (app-level, not blueprint)
- Fix events calendar nav: wrap multiple SX parts in fragment

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

account/sxc/pages/account.sx

@@ -18,7 +18,10 @@
   :path "/newsletters/"
   :auth :login
   :layout :account
-  :content (newsletters-content))
+  :data (newsletters-data)
+  :content (~account-newsletters-content
+    :newsletter-list newsletter-list
+    :account-url account-url))
 
 ;; ---------------------------------------------------------------------------
 ;; Fragment pages (tickets, bookings, etc. from events service)
@@ -28,4 +31,10 @@
   :path "/<slug>/"
   :auth :login
   :layout :account
-  :content (fragment-content slug))
+  :content (let* ((user (current-user))
+                  (result (frag "events" "account-page"
+                            :slug slug
+                            :user-id (str (get user "id")))))
+             (if (or (nil? result) (empty? result))
+               (abort 404)
+               result)))