Add retail/restaurant mode toggle to the register

A segmented Retail | Restaurant control in the register header flips the
location's service_style in place (RegisterController@setMode → pos.mode.set).
Switching to restaurant lands on the Floor and reveals Floor/Kitchen/Menu in the
sidebar; switching to retail stays on the register. Covered by PosRestaurantTest.

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

app/Http/Controllers/Pos/RegisterController.php

@@ -4,6 +4,7 @@ namespace App\Http\Controllers\Pos;
 
 use App\Http\Controllers\Controller;
 use App\Http\Controllers\Pos\Concerns\ScopesToAccount;
+use App\Models\PosLocation;
 use App\Models\PosProduct;
 use App\Models\PosSale;
 use App\Services\Pos\PosLocationService;
@@ -37,6 +38,21 @@ class RegisterController extends Controller
         ]);
     }
 
+    /** Quick switch between retail and restaurant service from the register. */
+    public function setMode(Request $request): RedirectResponse
+    {
+        $data = $request->validate(['style' => ['required', 'in:retail,restaurant']]);
+
+        $location = $this->locations->ensureDefault($this->ownerRef($request));
+        $location->update(['service_style' => $data['style']]);
+
+        if ($data['style'] === PosLocation::STYLE_RESTAURANT) {
+            return redirect()->route('pos.floor')->with('success', 'Restaurant mode on — Floor, Kitchen & Menu are now in the sidebar.');
+        }
+
+        return redirect()->route('pos.register')->with('success', 'Retail mode on.');
+    }
+
     /** @return list<array<string, mixed>> */
     private function crmCustomers(string $owner): array
     {