add contextual prompts for skipped setup steps

Disable checkout when Stripe isn't connected (cart drawer, cart page,
and early guard in checkout controller to prevent orphaned orders).
Show amber warning on order detail when email isn't configured.
Fix pre-existing missing vertical spacing between page blocks.

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

lib/berrypod_web/components/shop_components/layout.ex

@@ -52,7 +52,7 @@ defmodule BerrypodWeb.ShopComponents.Layout do
     cart_subtotal cart_total cart_drawer_open cart_status active_page error_page is_admin
     search_query search_results search_open categories shipping_estimate
     country_code available_countries editing editor_current_path editor_sidebar_open
-    header_nav_items footer_nav_items newsletter_enabled newsletter_state)a
+    header_nav_items footer_nav_items newsletter_enabled newsletter_state stripe_connected)a
 
   @doc """
   Extracts the assigns relevant to `shop_layout` from a full assigns map.
@@ -101,6 +101,7 @@ defmodule BerrypodWeb.ShopComponents.Layout do
   attr :footer_nav_items, :list, default: []
   attr :newsletter_enabled, :boolean, default: false
   attr :newsletter_state, :atom, default: :idle
+  attr :stripe_connected, :boolean, default: true
 
   slot :inner_block, required: true
 
@@ -156,6 +157,7 @@ defmodule BerrypodWeb.ShopComponents.Layout do
         shipping_estimate={@shipping_estimate}
         country_code={@country_code}
         available_countries={@available_countries}
+        stripe_connected={@stripe_connected}
       />
 
       <.search_modal