integrate R module and add url editor ui

Replaces hardcoded paths with R module throughout:
- Shop components: layout nav, cart, product links
- Controllers: cart, checkout, contact, seo, order lookup
- Shop pages: collection, product, search, checkout success, etc.
- Site context: nav item url resolution

Admin URL management:
- Settings page: prefix editor with validation feedback
- Page renderer: url_editor component for page URLs
- CSS for url editor styling

Test updates for cache isolation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lib/berrypod_web/live/shop/pages/content.ex

@@ -9,6 +9,7 @@ defmodule BerrypodWeb.Shop.Pages.Content do
   alias Berrypod.LegalPages
   alias Berrypod.Pages
   alias Berrypod.Theme.PreviewData
+  alias BerrypodWeb.R
 
   def init(socket, _params, _uri) do
     # Content pages load in handle_params based on live_action
@@ -38,7 +39,7 @@ defmodule BerrypodWeb.Shop.Pages.Content do
       %{
         page_title: "About",
         page_description: "Your story goes here – this is sample content for the demo shop",
-        og_url: BerrypodWeb.Endpoint.url() <> "/about"
+        og_url: R.url(R.about())
       },
       PreviewData.about_content()
     }
@@ -49,7 +50,7 @@ defmodule BerrypodWeb.Shop.Pages.Content do
       %{
         page_title: "Delivery & returns",
         page_description: "Everything you need to know about shipping and returns.",
-        og_url: BerrypodWeb.Endpoint.url() <> "/delivery"
+        og_url: R.url(R.delivery())
       },
       LegalPages.delivery_content()
     }
@@ -60,7 +61,7 @@ defmodule BerrypodWeb.Shop.Pages.Content do
       %{
         page_title: "Privacy policy",
         page_description: "How we handle your personal information.",
-        og_url: BerrypodWeb.Endpoint.url() <> "/privacy"
+        og_url: R.url(R.privacy())
       },
       LegalPages.privacy_content()
     }
@@ -71,7 +72,7 @@ defmodule BerrypodWeb.Shop.Pages.Content do
       %{
         page_title: "Terms of service",
         page_description: "The terms and conditions governing purchases from our shop.",
-        og_url: BerrypodWeb.Endpoint.url() <> "/terms"
+        og_url: R.url(R.terms())
       },
       LegalPages.terms_content()
     }