clear page-specific assigns on navigation to prevent stale data

When navigating between page types in the unified shop LiveView,
assigns from the previous page could persist and cause stale data
to appear or template errors. Now explicitly nils them out.

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

lib/berrypod_web/live/shop/page.ex

@@ -49,8 +49,11 @@ defmodule BerrypodWeb.Shop.Page do
 
     socket =
       if action != prev_action do
-        # Page type changed - call init
+        # Page type changed - clear previous page's assigns and call init
-        socket = assign(socket, :_current_page_action, action)
+        socket =
+          socket
+          |> assign(:_current_page_action, action)
+          |> clear_page_specific_assigns(prev_action)
 
         result =
           if action in @session_pages do
@@ -151,4 +154,61 @@ defmodule BerrypodWeb.Shop.Page do
   end
 
   defp maybe_cleanup_previous_page(socket, _), do: socket
+
+  # Clear assigns that are specific to each page type to prevent stale data
+  # from bleeding into the next page's render
+  defp clear_page_specific_assigns(socket, :product) do
+    socket
+    |> assign(:product, nil)
+    |> assign(:all_images, nil)
+    |> assign(:variants, nil)
+    |> assign(:option_types, nil)
+    |> assign(:selected_variant, nil)
+    |> assign(:selected_options, nil)
+    |> assign(:available_options, nil)
+    |> assign(:display_price, nil)
+    |> assign(:gallery_images, nil)
+    |> assign(:option_urls, nil)
+    |> assign(:related_products, nil)
+    |> assign(:json_ld, nil)
+  end
+
+  defp clear_page_specific_assigns(socket, :collection) do
+    socket
+    |> assign(:products, nil)
+    |> assign(:pagination, nil)
+    |> assign(:current_sort, nil)
+    |> assign(:collection_title, nil)
+    |> assign(:collection_slug, nil)
+  end
+
+  defp clear_page_specific_assigns(socket, :contact) do
+    socket
+    |> assign(:contact_form, nil)
+    |> assign(:lookup_form, nil)
+    |> assign(:looked_up_orders, nil)
+  end
+
+  defp clear_page_specific_assigns(socket, :search) do
+    assign(socket, :search_results, nil)
+  end
+
+  defp clear_page_specific_assigns(socket, :orders) do
+    assign(socket, :orders, nil)
+  end
+
+  defp clear_page_specific_assigns(socket, :order_detail) do
+    socket
+    |> assign(:order, nil)
+    |> assign(:email_form, nil)
+  end
+
+  defp clear_page_specific_assigns(socket, :checkout_success) do
+    socket
+    |> assign(:order, nil)
+    |> assign(:js_purchase_tracked, nil)
+    |> assign(:css_purchase_tracked, nil)
+  end
+
+  defp clear_page_specific_assigns(socket, _), do: socket
 end