extract setup wizard to dedicated /admin/setup page

Move the setup stepper out of the dashboard into its own LiveView.
Dashboard now redirects to setup when site isn't live, and shows
stats-only view once live. Also cleans up button component variant
handling, fixes alert CSS, and removes stale demo.html.

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

lib/berrypod/products.ex

@@ -90,6 +90,13 @@ defmodule Berrypod.Products do
     |> Repo.update_all(set: [sync_status: "idle"])
   end
 
+  @doc """
+  Returns the total count of all products.
+  """
+  def count_products do
+    Repo.aggregate(Product, :count)
+  end
+
   @doc """
   Returns the count of products for a provider connection.
   """