test fixes and new product advisories work

src/__Libraries/StellaOps.TestKit/Observability/ContractViolationException.cs

@@ -0,0 +1,29 @@
+namespace StellaOps.TestKit.Observability;
+
+/// <summary>
+/// Exception thrown when an observability contract assertion fails.
+/// </summary>
+/// <remarks>
+/// Contract violations indicate that telemetry output doesn't conform to
+/// expected schemas, cardinality limits, or data quality requirements.
+/// </remarks>
+public sealed class ContractViolationException : Exception
+{
+    /// <summary>
+    /// Creates a new contract violation exception.
+    /// </summary>
+    /// <param name="message">Description of the contract violation.</param>
+    public ContractViolationException(string message) : base(message)
+    {
+    }
+
+    /// <summary>
+    /// Creates a new contract violation exception with an inner exception.
+    /// </summary>
+    /// <param name="message">Description of the contract violation.</param>
+    /// <param name="innerException">The underlying exception.</param>
+    public ContractViolationException(string message, Exception innerException)
+        : base(message, innerException)
+    {
+    }
+}