Tighten payment sheet UI to match POS single-surface checkout.

When Paystack Inline is ready: widen desktop panel for channel sidebar, collapse
to a minimal header, hide footer trust line, and re-pin the checkout iframe to
the sheet body so it does not read as a second modal on top of Ladill chrome.

tests/Feature/ResponsivePaystackSheetTest.php

@@ -23,6 +23,8 @@ class ResponsivePaystackSheetTest extends TestCase
         $this->assertStringContainsString('rounded-t-2xl', $html);
         $this->assertStringContainsString('md:rounded-2xl', $html);
         $this->assertStringContainsString('md:max-w-lg', $html);
+        $this->assertStringContainsString('md:max-w-3xl', $html);
+        $this->assertStringContainsString('data-ladill-pay-header-minimal', $html);
         $this->assertStringContainsString('Complete your payment', $html);
         $this->assertStringContainsString('safe-area-inset-bottom', $html);
         $this->assertStringContainsString('LadillPayCheckout', $html);