add setup onboarding page, dashboard launch checklist, provider registry

- new /setup page with three-section onboarding (account, provider, payments)
- dashboard launch checklist with progress bar, go-live, dismiss
- provider registry on Provider module (single source of truth for metadata)
- payments registry for Stripe
- setup context made provider-agnostic (provider_connected, theme_customised, etc.)
- admin provider pages now fully registry-driven (no hardcoded provider names)
- auth flow: fresh installs redirect to /setup, signed_in_path respects setup state
- removed old /admin/setup wizard
- 840 tests, 0 failures

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

test/berrypod_web/live/shop/coming_soon_test.exs

@@ -51,9 +51,9 @@ defmodule BerrypodWeb.Shop.ComingSoonTest do
       assert html =~ "Shop the collection"
     end
 
-    test "redirects to registration on fresh install (no admin)", %{conn: conn} do
-      # No admin created — redirect to registration
-      assert {:error, {:redirect, %{to: "/users/register"}}} = live(conn, ~p"/")
+    test "redirects to setup on fresh install (no admin)", %{conn: conn} do
+      # No admin created — redirect to setup
+      assert {:error, {:redirect, %{to: "/setup"}}} = live(conn, ~p"/")
     end
 
     test "redirects when session token is stale (user deleted)", %{conn: conn} do
@@ -63,7 +63,7 @@ defmodule BerrypodWeb.Shop.ComingSoonTest do
       # Delete the user — session cookie is now stale
       Berrypod.Repo.delete!(user)
 
-      assert {:error, {:redirect, %{to: "/users/register"}}} = live(conn, ~p"/")
+      assert {:error, {:redirect, %{to: "/setup"}}} = live(conn, ~p"/")
     end
 
     test "gates all public shop routes", %{conn: conn} do