Exempt Mini Pay POSTs from Link CSRF checks.

Proxied ladl.link/{slug}/pay requests carry CSRF tokens from Mini HTML, which cannot bind to Link's session — the same 419 failure mode as event registration.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/Feature/LinkRedirectTest.php

@@ -233,4 +233,46 @@ class LinkRedirectTest extends TestCase
             ->assertOk()
             ->assertJsonPath('badge_code', 'BADGE123');
     }
+
+    public function test_mini_pay_post_does_not_require_link_app_csrf_token(): void
+    {
+        $user = $this->user();
+        ShortLink::create([
+            'user_id' => $user->id,
+            'slug' => 'shop-pay',
+            'source_app' => 'mini',
+            'source_kind' => 'qr',
+            'is_managed_here' => false,
+            'destination_url' => 'https://ladl.link/shop-pay',
+            'is_active' => true,
+        ]);
+
+        Http::fake([
+            'https://ladill.com/q/shop-pay/pay' => Http::response(json_encode([
+                'checkout_url' => 'https://ladill.com/pay/momo/REF123',
+                'provider' => 'mtn_momo',
+            ]), 200, ['Content-Type' => 'application/json']),
+        ]);
+
+        $this->postJson('https://ladl.link/shop-pay/pay', [
+            'amount' => 12.5,
+            'customer_phone' => '0241234567',
+        ])
+            ->assertOk()
+            ->assertJsonPath('provider', 'mtn_momo')
+            ->assertJsonPath('checkout_url', 'https://ladill.com/pay/momo/REF123');
+
+        Http::assertSent(function ($request) {
+            if ($request->url() !== 'https://ladill.com/q/shop-pay/pay') {
+                return false;
+            }
+
+            $payload = json_decode($request->body(), true);
+
+            return is_array($payload)
+                && (float) ($payload['amount'] ?? 0) === 12.5
+                && ($payload['customer_phone'] ?? '') === '0241234567'
+                && $request->hasHeader('X-Ladill-Internal', '1');
+        });
+    }
 }