feat: wire shop LiveViews to real product data

PreviewData now queries the Products context when real products exist,
falling back to mock data otherwise. Shop pages automatically display
synced Printify products.

Fixes:
- Printify image position was string ("front"), now uses index
- Category extraction improved to match more Printify tags
- ProductShow finds products by slug for real data

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

lib/simpleshop_theme/theme/preview_data.ex

@@ -6,6 +6,8 @@ defmodule SimpleshopTheme.Theme.PreviewData do
   This allows users to preview themes before adding products to their shop.
   """
 
+  alias SimpleshopTheme.Products
+
   @doc """
   Returns products for preview.
 
@@ -167,22 +169,81 @@ defmodule SimpleshopTheme.Theme.PreviewData do
   @doc """
   Checks if the shop has real products.
 
-  Returns true if at least one product exists in the database.
+  Returns true if at least one visible, active product exists in the database.
+  Returns false if the database is unavailable (e.g., in tests without sandbox).
   """
   def has_real_products? do
-    false
+    try do
+      Products.list_products(visible: true, status: "active") |> Enum.any?()
+    rescue
+      DBConnection.OwnershipError -> false
+    end
   end
 
   defp has_real_categories? do
-    false
+    has_real_products?()
   end
 
   defp get_real_products do
-    []
+    Products.list_products(visible: true, status: "active", preload: [:images, :variants])
+    |> Enum.map(&product_to_map/1)
   end
 
   defp get_real_categories do
-    []
+    Products.list_products(visible: true, status: "active")
+    |> Enum.map(& &1.category)
+    |> Enum.reject(&is_nil/1)
+    |> Enum.frequencies()
+    |> Enum.map(fn {name, count} ->
+      %{
+        id: Slug.slugify(name),
+        name: name,
+        slug: Slug.slugify(name),
+        product_count: count,
+        image_url: nil
+      }
+    end)
+    |> Enum.sort_by(& &1.name)
+  end
+
+  # Transform a Product struct to the map format expected by shop components
+  defp product_to_map(product) do
+    # Get images sorted by position
+    images = Enum.sort_by(product.images, & &1.position)
+    first_image = List.first(images)
+    second_image = Enum.at(images, 1)
+
+    # Get available variants for pricing
+    available_variants =
+      product.variants
+      |> Enum.filter(& &1.is_enabled)
+      |> Enum.filter(& &1.is_available)
+
+    # Get the cheapest available variant for display price
+    cheapest_variant =
+      available_variants
+      |> Enum.min_by(& &1.price, fn -> nil end)
+
+    # Determine stock and sale status
+    in_stock = Enum.any?(available_variants)
+    on_sale = Enum.any?(product.variants, &SimpleshopTheme.Products.ProductVariant.on_sale?/1)
+
+    %{
+      id: product.slug,
+      name: product.title,
+      description: product.description,
+      price: if(cheapest_variant, do: cheapest_variant.price, else: 0),
+      compare_at_price: if(cheapest_variant, do: cheapest_variant.compare_at_price, else: nil),
+      image_url: if(first_image, do: first_image.src, else: nil),
+      hover_image_url: if(second_image, do: second_image.src, else: nil),
+      source_width: nil,
+      hover_source_width: nil,
+      category: product.category,
+      slug: product.slug,
+      in_stock: in_stock,
+      on_sale: on_sale,
+      inserted_at: product.inserted_at
+    }
   end
 
   # Default source width for mockup variants (max generated size)