add denormalized product fields and use Product structs throughout

Adds cheapest_price, compare_at_price, in_stock, on_sale columns to
products table (recomputed from variants after each sync). Shop
components now work with Product structs directly instead of plain
maps from PreviewData. Renames .name to .title, adds Product display
helpers (primary_image, hover_image, option_types) and ProductImage
helpers (display_url, direct_url, source_width). Adds Products context
query functions for storefront use (list_visible_products,
get_visible_product, list_categories with DB-level sort/filter).

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

test/simpleshop_theme_web/live/shop/collection_test.exs

@@ -32,7 +32,7 @@ defmodule SimpleshopThemeWeb.Shop.CollectionTest do
       products = PreviewData.products()
       first_product = List.first(products)
 
-      assert html =~ first_product.name
+      assert html =~ first_product.title
     end
 
     test "displays category filter buttons", %{conn: conn} do
@@ -71,7 +71,7 @@ defmodule SimpleshopThemeWeb.Shop.CollectionTest do
       products = PreviewData.products_by_category(category.slug)
 
       for product <- products do
-        assert html =~ product.name
+        assert html =~ product.title
       end
     end
   end

test/simpleshop_theme_web/live/shop/home_test.exs

@@ -43,7 +43,7 @@ defmodule SimpleshopThemeWeb.Shop.HomeTest do
       products = PreviewData.products()
       first_product = List.first(products)
 
-      assert html =~ first_product.name
+      assert html =~ first_product.title
     end
 
     test "renders image and text section", %{conn: conn} do

test/simpleshop_theme_web/live/shop/product_show_test.exs

@@ -17,7 +17,7 @@ defmodule SimpleshopThemeWeb.Shop.ProductShowTest do
       product = List.first(PreviewData.products())
       {:ok, _view, html} = live(conn, ~p"/products/#{product.id}")
 
-      assert html =~ product.name
+      assert html =~ product.title
     end
 
     test "renders product description", %{conn: conn} do
@@ -31,7 +31,7 @@ defmodule SimpleshopThemeWeb.Shop.ProductShowTest do
       product = List.first(PreviewData.products())
       {:ok, _view, html} = live(conn, ~p"/products/#{product.id}")
 
-      assert html =~ SimpleshopTheme.Cart.format_price(product.price)
+      assert html =~ SimpleshopTheme.Cart.format_price(product.cheapest_price)
     end
 
     test "renders breadcrumb with category link", %{conn: conn} do
@@ -55,7 +55,7 @@ defmodule SimpleshopThemeWeb.Shop.ProductShowTest do
 
       # Should show other products, not the current one
       other_product = Enum.at(PreviewData.products(), 1)
-      assert html =~ other_product.name
+      assert html =~ other_product.title
     end
   end
 
@@ -213,8 +213,8 @@ defmodule SimpleshopThemeWeb.Shop.ProductShowTest do
       product = List.first(PreviewData.products())
 
       # Each image should have descriptive alt text
-      assert html =~ "#{product.name} — image 1 of"
-      assert html =~ "#{product.name} — image 2 of"
+      assert html =~ "#{product.title} — image 1 of"
+      assert html =~ "#{product.title} — image 2 of"
     end
 
     test "renders dot indicators for multi-image gallery", %{conn: conn} do
@@ -278,14 +278,14 @@ defmodule SimpleshopThemeWeb.Shop.ProductShowTest do
       product = Enum.at(PreviewData.products(), 1)
       {:ok, _view, html} = live(conn, ~p"/products/#{product.id}")
 
-      assert html =~ product.name
+      assert html =~ product.title
     end
 
     test "falls back to first product for unknown ID", %{conn: conn} do
       {:ok, _view, html} = live(conn, ~p"/products/nonexistent")
 
       first_product = List.first(PreviewData.products())
-      assert html =~ first_product.name
+      assert html =~ first_product.title
     end
   end
 end