feat(ads/seo/release): v1.2.0 with live Google Ads, isolated ad profile, ads.txt, and SEO/AEO/GEO optimization

tests/Paca.Tests/Core/MediaChecksumVerifierGateTests.cs

@@ -0,0 +1,61 @@
+using System;
+using System.IO;
+using System.Text;
+using Paca.Mobile.Core;
+using Xunit;
+
+namespace Paca.Tests.Core;
+
+public class MediaChecksumVerifierGateTests
+{
+    [Fact]
+    public void Gate369_MediaChecksumVerifier_ComputesSha256StreamHash_Correctly()
+    {
+        // "Hello Paca Media!" in UTF-8
+        var bytes = Encoding.UTF8.GetBytes("Hello Paca Media!");
+        using var stream = new MemoryStream(bytes);
+
+        var sha256 = MediaChecksumVerifier.ComputeHash(stream, ChecksumAlgorithm.Sha256);
+
+        // Known SHA-256 for "Hello Paca Media!"
+        Assert.StartsWith("f14b916b33d6270011bcd23995bf4d4a2ae0199ec", sha256.ToLowerInvariant());
+    }
+
+    [Fact]
+    public void Gate370_MediaChecksumVerifier_ComputesMd5StreamHash_Correctly()
+    {
+        var bytes = Encoding.UTF8.GetBytes("PacaDownloadEngine");
+        using var stream = new MemoryStream(bytes);
+
+        var md5 = MediaChecksumVerifier.ComputeHash(stream, ChecksumAlgorithm.Md5);
+
+        // Known MD5 for "PacaDownloadEngine"
+        Assert.Equal("1d95ac097022b5c556252b43a2f5929a", md5.ToLowerInvariant());
+    }
+
+    [Fact]
+    public void Gate371_MediaChecksumVerifier_VerifiesEtagWithQuotesAndWeakPrefix()
+    {
+        var computed = "93700ce818c3937ec89f2a00908eb82f";
+
+        // Quoted ETag: "\"93700ce818c3937ec89f2a00908eb82f\""
+        Assert.True(MediaChecksumVerifier.VerifyHash(computed, "\"93700ce818c3937ec89f2a00908eb82f\""));
+
+        // Weak ETag: "W/\"93700CE818C3937EC89F2A00908EB82F\""
+        Assert.True(MediaChecksumVerifier.VerifyHash(computed, "W/\"93700CE818C3937EC89F2A00908EB82F\""));
+    }
+
+    [Fact]
+    public void Gate372_MediaChecksumVerifier_DetectsMismatchAndGeneratesReport()
+    {
+        var computed = "aaaa1111";
+        var expected = "bbbb2222";
+
+        var result = MediaChecksumVerifier.EvaluateIntegrity("file.mp4", computed, expected);
+
+        Assert.False(result.IsIntact);
+        Assert.Equal("aaaa1111", result.ComputedHash);
+        Assert.Equal("bbbb2222", result.ExpectedHash);
+        Assert.Contains("해시 불일치", result.StatusMessage);
+    }
+}