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/ThumbnailScrubberPreviewGateTests.cs

@@ -0,0 +1,61 @@
+using System;
+using Paca.Mobile.Core;
+using Xunit;
+
+namespace Paca.Tests.Core;
+
+public class ThumbnailScrubberPreviewGateTests
+{
+    [Fact]
+    public void Gate241_ThumbnailScrubberPreview_CalculatesTimestamp_AndFormatsProperly()
+    {
+        Assert.Equal("00:45", ThumbnailScrubberPreview.FormatTimestamp(45.2));
+        Assert.Equal("01:01:05", ThumbnailScrubberPreview.FormatTimestamp(3665.0));
+        Assert.Equal("00:00", ThumbnailScrubberPreview.FormatTimestamp(0));
+    }
+
+    [Fact]
+    public void Gate242_ThumbnailScrubberPreview_CalculatesThumbnailUrl_WithSeekQuery()
+    {
+        var preview = new ThumbnailScrubberPreview("media-123", totalDurationSec: 200.0);
+        var url = preview.GetPreviewUrlForRatio(0.5); // 100s
+
+        Assert.Contains("/api/library/media-123/thumb", url);
+        Assert.Contains("t=100", url);
+    }
+
+    [Fact]
+    public void Gate243_ThumbnailScrubberPreview_ClampsSeekPositionWithinBounds()
+    {
+        var preview = new ThumbnailScrubberPreview("media-999", totalDurationSec: 100.0);
+
+        // Underflow clamp
+        var underflowTime = preview.GetClampedSeekTime(-0.1);
+        Assert.Equal(0.0, underflowTime);
+
+        // Overflow clamp
+        var overflowTime = preview.GetClampedSeekTime(1.5);
+        Assert.Equal(100.0, overflowTime);
+    }
+
+    [Fact]
+    public void Gate244_ThumbnailScrubberPreview_LruCache_EvictsOldestWhenLimitReached()
+    {
+        var cache = new ScrubberPreviewCache(capacity: 3);
+
+        cache.Put("t=10", new byte[] { 1 });
+        cache.Put("t=20", new byte[] { 2 });
+        cache.Put("t=30", new byte[] { 3 });
+
+        Assert.True(cache.TryGet("t=10", out _));
+        Assert.True(cache.TryGet("t=20", out _));
+        Assert.True(cache.TryGet("t=30", out _));
+
+        // Add 4th item, oldest accessed was t=10 before t=20/t=30, now add t=40
+        cache.Put("t=40", new byte[] { 4 });
+
+        Assert.Equal(3, cache.Count);
+        // t=40 is in cache
+        Assert.True(cache.TryGet("t=40", out _));
+    }
+}