1.3 Orientation value type

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/FrameProcessor.Tests/OrientationTests.cs

@@ -0,0 +1,46 @@
+using System.Text.Json;
+using FrameProcessor.Domain;
+
+namespace FrameProcessor.Tests;
+
+public class OrientationTests
+{
+    [Theory]
+    [InlineData("\"landscape\"", Orientation.Landscape)]
+    [InlineData("\"portrait\"", Orientation.Portrait)]
+    public void JsonDeserialize_KebabCaseLowercase(string json, Orientation expected)
+    {
+        var value = JsonSerializer.Deserialize<Orientation>(json);
+        Assert.Equal(expected, value);
+    }
+
+    [Theory]
+    [InlineData(Orientation.Landscape, "\"landscape\"")]
+    [InlineData(Orientation.Portrait, "\"portrait\"")]
+    public void JsonSerialize_KebabCaseLowercase(Orientation value, string expected)
+    {
+        var json = JsonSerializer.Serialize(value);
+        Assert.Equal(expected, json);
+    }
+
+    [Theory]
+    [InlineData("\"Landscape\"")]
+    [InlineData("\"PORTRAIT\"")]
+    [InlineData("\"diagonal\"")]
+    [InlineData("\"\"")]
+    public void JsonDeserialize_RejectsInvalid(string json)
+    {
+        Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<Orientation>(json));
+    }
+
+    [Fact]
+    public void JsonRoundTrip_PreservesValue()
+    {
+        foreach (var value in new[] { Orientation.Landscape, Orientation.Portrait })
+        {
+            var json = JsonSerializer.Serialize(value);
+            var roundTripped = JsonSerializer.Deserialize<Orientation>(json);
+            Assert.Equal(value, roundTripped);
+        }
+    }
+}