feat: add default content pages for delivery, privacy and terms

Replace one-off ShopLive.About with generic ShopLive.Content that
handles all static content pages via live_action. Add delivery &
returns, privacy policy, and terms of service pages with sample
content. Update footer help links and theme editor preview.

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

lib/simpleshop_theme_web/live/theme_live/index.ex

@@ -431,11 +431,75 @@ defmodule SimpleshopThemeWeb.ThemeLive.Index do
 
   defp preview_page(%{page: :about} = assigns) do
     ~H"""
-    <SimpleshopThemeWeb.PageTemplates.about
+    <SimpleshopThemeWeb.PageTemplates.content
       theme_settings={@theme_settings}
       logo_image={@logo_image}
       header_image={@header_image}
       mode={:preview}
+      active_page="about"
+      hero_title="About the studio"
+      hero_description="Your story goes here – this is sample content for the demo shop"
+      hero_background={:sunken}
+      image_src="/mockups/night-sky-blanket-3"
+      image_alt="Night sky blanket draped over a chair"
+      content_blocks={PreviewData.about_content()}
+      cart_items={PreviewData.cart_drawer_items()}
+      cart_count={2}
+      cart_subtotal="£72.00"
+      cart_drawer_open={@cart_drawer_open}
+    />
+    """
+  end
+
+  defp preview_page(%{page: :delivery} = assigns) do
+    ~H"""
+    <SimpleshopThemeWeb.PageTemplates.content
+      theme_settings={@theme_settings}
+      logo_image={@logo_image}
+      header_image={@header_image}
+      mode={:preview}
+      active_page="delivery"
+      hero_title="Delivery & returns"
+      hero_description="Everything you need to know about shipping and returns"
+      content_blocks={PreviewData.delivery_content()}
+      cart_items={PreviewData.cart_drawer_items()}
+      cart_count={2}
+      cart_subtotal="£72.00"
+      cart_drawer_open={@cart_drawer_open}
+    />
+    """
+  end
+
+  defp preview_page(%{page: :privacy} = assigns) do
+    ~H"""
+    <SimpleshopThemeWeb.PageTemplates.content
+      theme_settings={@theme_settings}
+      logo_image={@logo_image}
+      header_image={@header_image}
+      mode={:preview}
+      active_page="privacy"
+      hero_title="Privacy policy"
+      hero_description="How we handle your personal information"
+      content_blocks={PreviewData.privacy_content()}
+      cart_items={PreviewData.cart_drawer_items()}
+      cart_count={2}
+      cart_subtotal="£72.00"
+      cart_drawer_open={@cart_drawer_open}
+    />
+    """
+  end
+
+  defp preview_page(%{page: :terms} = assigns) do
+    ~H"""
+    <SimpleshopThemeWeb.PageTemplates.content
+      theme_settings={@theme_settings}
+      logo_image={@logo_image}
+      header_image={@header_image}
+      mode={:preview}
+      active_page="terms"
+      hero_title="Terms of service"
+      hero_description="The legal bits"
+      content_blocks={PreviewData.terms_content()}
       cart_items={PreviewData.cart_drawer_items()}
       cart_count={2}
       cart_subtotal="£72.00"

lib/simpleshop_theme_web/live/theme_live/index.html.heex

@@ -1091,6 +1091,9 @@
             {:pdp, "Product"},
             {:cart, "Cart"},
             {:about, "About"},
+            {:delivery, "Delivery"},
+            {:privacy, "Privacy"},
+            {:terms, "Terms"},
             {:contact, "Contact"},
             {:error, "404"}
           ] do %>