Pass all values as &key args to ~root-header/~root-mobile

Nested component calls in _aser are serialized without body expansion,
so free variables inside ~root-header would be sent unresolved to the
client. Fix by making ~root-header/~root-mobile take all values as
&key params, and having parent layout defcomps pass them explicitly.
The parent layout bodies ARE expanded (via async_eval_slot_to_sx),
so their free variables resolve correctly during that expansion.

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

federation/sx/layouts.sx

@@ -3,7 +3,9 @@
 
 ;; Full page: root header + social header in header-child
 (defcomp ~social-layout-full ()
-  (<> (~root-header)
+  (<> (~root-header :cart-mini cart-mini :blog-url blog-url :site-title site-title
+                     :app-label app-label :nav-tree nav-tree :auth-menu auth-menu
+                     :nav-panel nav-panel :settings-url settings-url :is-admin is-admin)
     (~header-child-sx
       :inner (~federation-social-header
                :nav (~federation-social-nav :actor actor)))))
@@ -14,4 +16,7 @@
         :parent-id "root-header-child"
         :row (~federation-social-header
                :nav (~federation-social-nav :actor actor)))
-    (~root-header :oob true)))
+    (~root-header :cart-mini cart-mini :blog-url blog-url :site-title site-title
+                   :app-label app-label :nav-tree nav-tree :auth-menu auth-menu
+                   :nav-panel nav-panel :settings-url settings-url :is-admin is-admin
+                   :oob true)))