feat: add suitelink client runtime and test harness

tests/SuiteLink.Client.Tests/Fixtures/FixtureBytes.cs

@@ -0,0 +1,10 @@
+namespace SuiteLink.Client.Tests.Fixtures;
+
+internal static class FixtureBytes
+{
+    public static byte[] Read(string fileName)
+    {
+        var path = Path.Combine(AppContext.BaseDirectory, "Fixtures", fileName);
+        return File.ReadAllBytes(path);
+    }
+}