feat: upgrade phpunit to 12.5

tests/Service/BookingPriceMismatchAnalyzerTest.php

@@ -19,7 +19,7 @@ class BookingPriceMismatchAnalyzerTest extends TestCase
 {
     public function testBuildDiagnosticsProvidesDeltaBreakdown(): void
     {
-        $pricingAssembler = $this->createMock(BookingPricingAssembler::class);
+        $pricingAssembler = $this->createStub(BookingPricingAssembler::class);
         $pricingAssembler->method('getPricingBreakdown')->willReturn([
             'rooms' => [
                 ['roomId' => 74, 'totalPrice' => 444.0],