Fix systemic extraction breakage in authenticated UI.

The give→merchant transform left several independent breakages that 500'd
once a logged-in user hit the pages:

- /storefronts/{create,show,update,...} were wired to Qr\QrCodeController,
  which renders events-lineage qr-codes.* views referencing 14 undefined
  events.* routes. Rewire to StorefrontController (clean storefronts.* views).
- storefronts/show.blade.php @include('give.storefronts.partials.*') — the
  view dir was renamed give→merchant but the include namespace wasn't.
- /payouts + /search queried qr_sale_orders.*_minor; migration created *_ghs.
- Remove dead GiveDonation model (nonexistent give_donations table).

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

app/Http/Controllers/SearchController.php

@@ -55,7 +55,7 @@ class SearchController extends Controller
             ->get()
             ->map(function (QrSaleOrder $order): array {
                 $amount = number_format(
-                    ($order->status === QrSaleOrder::STATUS_PAID ? $order->merchant_amount_minor : $order->amount_minor) / 100,
+                    (float) ($order->status === QrSaleOrder::STATUS_PAID ? $order->merchant_amount_ghs : $order->amount_ghs),
                     2,
                 );