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/bp/fragments/routes.py

@@ -59,9 +59,10 @@ def register():
             href = app_slugs.get(item.slug, blog_url(f"/{item.slug}/"))
             selected = "true" if (item.slug == first_seg
                                   or item.slug == app_name) else "false"
-            img = sx_call("blog-nav-item-image",
+            img = sx_call("img-or-placeholder",
                             src=getattr(item, "feature_image", None),
-                            label=getattr(item, "label", item.slug))
+                            alt=getattr(item, "label", item.slug),
+                            size_cls="w-8 h-8 rounded-full object-cover flex-shrink-0")
             item_sxs.append(sx_call(
                 "blog-nav-item-link",
                 href=href, hx_get=href, selected=selected, nav_cls=nav_cls,
@@ -72,7 +73,8 @@ def register():
         href = artdag_url("/")
         selected = "true" if ("artdag" == first_seg
                               or "artdag" == app_name) else "false"
-        img = sx_call("blog-nav-item-image", src=None, label="art-dag")
+        img = sx_call("img-or-placeholder", src=None, alt="art-dag",
+                          size_cls="w-8 h-8 rounded-full object-cover flex-shrink-0")
         item_sxs.append(sx_call(
             "blog-nav-item-link",
             href=href, hx_get=href, selected=selected, nav_cls=nav_cls,
@@ -101,13 +103,15 @@ def register():
         right_hs = ("on click set #" + container_id
                      + ".scrollLeft to #" + container_id + ".scrollLeft + 200")
 
-        return sx_call("blog-nav-wrapper",
-                         arrow_cls=arrow_cls,
+        return sx_call("scroll-nav-wrapper",
+                         wrapper_id="menu-items-nav-wrapper",
                          container_id=container_id,
+                         arrow_cls=arrow_cls,
                          left_hs=left_hs,
                          scroll_hs=scroll_hs,
                          right_hs=right_hs,
-                         items=SxExpr(items_frag))
+                         items=SxExpr(items_frag),
+                         oob=True)
 
     _handlers["nav-tree"] = _nav_tree_handler