Refactor SX templates: shared components, Python migration, cleanup

- Extract shared components (empty-state, delete-btn, sentinel, crud-*,
  view-toggle, img-or-placeholder, avatar, sumup-settings-form, auth
  forms, order tables/detail/checkout)
- Migrate all Python sx_call() callers to use shared components directly
- Remove 55+ thin wrapper defcomps from domain .sx files
- Remove trivial passthrough wrappers (blog-header-label, market-card-text, etc)
- Unify duplicate auth flows (account + federation) into shared/sx/templates/auth.sx
- Unify duplicate order views (cart + orders) into shared/sx/templates/orders.sx
- Disable static file caching in dev (SEND_FILE_MAX_AGE_DEFAULT=0)
- Add SX response validation and debug headers

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

blog/sx/admin.sx

@@ -14,12 +14,6 @@
       (h1 :class "text-3xl font-bold" "Snippets"))
     (div :id "snippets-list" list)))
 
-(defcomp ~blog-snippets-empty ()
-  (div :class "bg-white rounded-lg shadow"
-    (div :class "p-8 text-center text-stone-400"
-      (i :class "fa fa-puzzle-piece text-4xl mb-2")
-      (p "No snippets yet. Create one from the blog editor."))))
-
 (defcomp ~blog-snippet-visibility-select (&key patch-url hx-headers options cls)
   (select :name "visibility" :sx-patch patch-url :sx-target "#snippets-list" :sx-swap "innerHTML"
     :sx-headers hx-headers :class "text-sm border border-stone-300 rounded px-2 py-1"
@@ -28,16 +22,6 @@
 (defcomp ~blog-snippet-option (&key value selected label)
   (option :value value :selected selected label))
 
-(defcomp ~blog-snippet-delete-button (&key confirm-text delete-url hx-headers)
-  (button :type "button" :data-confirm "" :data-confirm-title "Delete snippet?"
-    :data-confirm-text confirm-text :data-confirm-icon "warning"
-    :data-confirm-confirm-text "Yes, delete" :data-confirm-cancel-text "Cancel"
-    :data-confirm-event "confirmed"
-    :sx-delete delete-url :sx-trigger "confirmed" :sx-target "#snippets-list" :sx-swap "innerHTML"
-    :sx-headers hx-headers
-    :class "px-3 py-1 text-sm bg-red-200 hover:bg-red-300 rounded text-red-800 flex-shrink-0"
-    (i :class "fa fa-trash") " Delete"))
-
 (defcomp ~blog-snippet-row (&key name owner badge-cls visibility extra)
   (div :class "flex items-center gap-4 p-4 hover:bg-stone-50 transition"
     (div :class "flex-1 min-w-0"
@@ -58,16 +42,6 @@
     (div :id "menu-item-form" :class "mb-6")
     (div :id "menu-items-list" list)))
 
-(defcomp ~blog-menu-items-empty ()
-  (div :class "bg-white rounded-lg shadow"
-    (div :class "p-8 text-center text-stone-400"
-      (i :class "fa fa-inbox text-4xl mb-2")
-      (p "No menu items yet. Add one to get started!"))))
-
-(defcomp ~blog-menu-item-image (&key src label)
-  (if src (img :src src :alt label :class "w-12 h-12 rounded-full object-cover flex-shrink-0")
-    (div :class "w-12 h-12 rounded-full bg-stone-200 flex-shrink-0")))
-
 (defcomp ~blog-menu-item-row (&key img label slug sort-order edit-url delete-url confirm-text hx-headers)
   (div :class "flex items-center gap-4 p-4 hover:bg-stone-50 transition"
     (div :class "text-stone-400 cursor-move" (i :class "fa fa-grip-vertical"))
@@ -80,14 +54,9 @@
       (button :type "button" :sx-get edit-url :sx-target "#menu-item-form" :sx-swap "innerHTML"
         :class "px-3 py-1 text-sm bg-stone-200 hover:bg-stone-300 rounded"
         (i :class "fa fa-edit") " Edit")
-      (button :type "button" :data-confirm "" :data-confirm-title "Delete menu item?"
-        :data-confirm-text confirm-text :data-confirm-icon "warning"
-        :data-confirm-confirm-text "Yes, delete" :data-confirm-cancel-text "Cancel"
-        :data-confirm-event "confirmed"
-        :sx-delete delete-url :sx-trigger "confirmed" :sx-target "#menu-items-list" :sx-swap "innerHTML"
-        :sx-headers hx-headers
-        :class "px-3 py-1 text-sm bg-red-200 hover:bg-red-300 rounded text-red-800"
-        (i :class "fa fa-trash") " Delete"))))
+      (~delete-btn :url delete-url :trigger-target "#menu-items-list"
+        :title "Delete menu item?" :text confirm-text
+        :sx-headers hx-headers))))
 
 (defcomp ~blog-menu-items-list (&key rows)
   (div :class "bg-white rounded-lg shadow" (div :class "divide-y" rows)))
@@ -123,9 +92,6 @@
 (defcomp ~blog-tag-groups-list (&key items)
   (ul :class "space-y-2" items))
 
-(defcomp ~blog-tag-groups-empty ()
-  (p :class "text-stone-500 text-sm" "No tag groups yet."))
-
 (defcomp ~blog-unassigned-tag (&key name)
   (span :class "inline-block bg-stone-100 text-stone-600 px-2 py-1 text-xs font-medium border border-stone-200 rounded" name))