test: repair test suite broken by feature drift (red -> 81 passing)

The test project no longer compiled: recent feature commits changed
interfaces and DTOs without updating the test doubles/call sites, so the
whole suite (and therefore CI) was failing to build.

- NoOpInventoryService: add IInventoryService.GetPurchasesSummaryAsync and
  the new string? userId param on AdjustAsync.
- NoOpLoyaltyService: add ILoyaltyService.RedeemOnOrderAsync.
- NoOpOrderNotificationService: add NotifyCallWaiterAsync.
- New NoOpAbuseProtectionService and NoOpMediaStorageService test doubles.
- QrMenuTests: ReviewService/PublicService gained IAbuseProtectionService +
  IHttpContextAccessor (and ReviewService an IMediaStorageService); wire the
  new no-op doubles + a real HttpContextAccessor.
- PrintingTests: OrderDto gained a DisplayNumber int between CreatedAt and
  Items; pass it.
- DiscoverFilterTests: add missing `using Xunit;` and the new openNow arg on
  DiscoverFilterParams.FromQuery.

Result: dotnet test -> Passed: 81, Failed: 0.

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

tests/Meezi.API.Tests/NoOpAbuseProtectionService.cs

@@ -0,0 +1,26 @@
+using Meezi.API.Security;
+
+namespace Meezi.API.Tests;
+
+/// <summary>Test double that allows every action and has no captcha configured.</summary>
+internal sealed class NoOpAbuseProtectionService : IAbuseProtectionService
+{
+    public bool IsCaptchaConfigured => false;
+    public string? CaptchaSiteKey => null;
+
+    public Task<(bool Allowed, string? ErrorCode, string? Message)> CheckAuthOtpByIpAsync(
+        string clientIp, CancellationToken cancellationToken = default) =>
+        Task.FromResult<(bool, string?, string?)>((true, null, null));
+
+    public Task<(bool Allowed, string? ErrorCode, string? Message)> CheckGuestOrderAsync(
+        string cafeId, string clientIp, CancellationToken cancellationToken = default) =>
+        Task.FromResult<(bool, string?, string?)>((true, null, null));
+
+    public Task<(bool Allowed, string? ErrorCode, string? Message)> CheckPublicWriteByIpAsync(
+        string clientIp, CancellationToken cancellationToken = default) =>
+        Task.FromResult<(bool, string?, string?)>((true, null, null));
+
+    public Task<(bool Ok, string? ErrorCode, string? Message)> VerifyCaptchaAsync(
+        string? captchaToken, CancellationToken cancellationToken = default) =>
+        Task.FromResult<(bool, string?, string?)>((true, null, null));
+}