Fix Mini fork leftovers in POS config

After an auto-logout, silent re-auth fails with login_required and
SsoLoginController@callback redirects to config('ladill.marketing_url') — which
still defaulted to https://ladill.com/products/mini, dumping POS users on Mini's
product page. Point ladill.product_slug/marketing_url at POS.

Also fix the identity service key (config/identity.php + services.ladill_identity
read IDENTITY_API_KEY_MINI; POS provisions IDENTITY_API_KEY_POS) and tidy the
remaining Mini defaults (app.name, ladill_sso redirect, mobile-topbar app_name).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

config/app.php

@@ -13,7 +13,7 @@ return [
     |
     */
 
-    'name' => env('APP_NAME', 'Ladill Mini'),
+    'name' => env('APP_NAME', 'Ladill POS'),
 
     /*
     |--------------------------------------------------------------------------