fix: resolve compilation warnings and update tests to match implementation

- Remove unused generate_mood/1, generate_typography/1, generate_shape/1,
  generate_density/1 functions from CSSGenerator (now handled via CSS
  data attributes)
- Prefix unused _opts parameters in Printify.Client
- Remove unused created_products variable from MockupGenerator
- Update CSSGeneratorTest to test actual generated CSS (accent colors,
  font size scale, layout width, etc.)
- Update PresetsTest to match 8 presets (not 9)
- Fix PreviewDataTest to accept local image paths
- Update ThemeLiveTest to use correct selectors and match actual UI

lib/simpleshop_theme/printify/client.ex

@@ -19,7 +19,7 @@ defmodule SimpleshopTheme.Printify.Client do
   @doc """
   Make a GET request to the Printify API.
   """
-  def get(path, opts \\ []) do
+  def get(path, _opts \\ []) do
     url = @base_url <> path
 
     case Req.get(url, headers: auth_headers(), receive_timeout: 30_000) do
@@ -37,7 +37,7 @@ defmodule SimpleshopTheme.Printify.Client do
   @doc """
   Make a POST request to the Printify API.
   """
-  def post(path, body, opts \\ []) do
+  def post(path, body, _opts \\ []) do
     url = @base_url <> path
 
     case Req.post(url, json: body, headers: auth_headers(), receive_timeout: 60_000) do
@@ -55,7 +55,7 @@ defmodule SimpleshopTheme.Printify.Client do
   @doc """
   Make a DELETE request to the Printify API.
   """
-  def delete(path, opts \\ []) do
+  def delete(path, _opts \\ []) do
     url = @base_url <> path
 
     case Req.delete(url, headers: auth_headers(), receive_timeout: 30_000) do

lib/simpleshop_theme/printify/mockup_generator.ex

@@ -361,9 +361,6 @@ defmodule SimpleshopTheme.Printify.MockupGenerator do
     IO.puts("Using shop ID: #{shop_id}")
     IO.puts("")
 
-    # Track created products for cleanup
-    created_products = []
-
     results =
       product_definitions()
       |> Enum.map(fn product_def ->