feat(weeztix): auto company from OAuth, remove company UI

Store company_guid after OAuth via profile API; drop company select and
companies endpoint. Coupons AJAX uses stored company only. Form request
no longer accepts company fields from the browser.

Made-with: Cursor

app/Http/Requests/Admin/UpdateWeeztixConfigRequest.php

@@ -44,8 +44,6 @@ class UpdateWeeztixConfigRequest extends FormRequest
                 'string',
                 'max:2048',
             ],
-            'company_guid' => ['nullable', 'string', 'max:255'],
-            'company_name' => ['nullable', 'string', 'max:255'],
             'coupon_guid' => ['nullable', 'string', 'max:255'],
             'coupon_name' => ['nullable', 'string', 'max:255'],
             'code_prefix' => ['nullable', 'string', 'max:32'],