Rename Vexer to Excititor

src/StellaOps.Excititor.Attestation/Signing/IVexSigner.cs

@@ -0,0 +1,12 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace StellaOps.Excititor.Attestation.Signing;
+
+public sealed record VexSignedPayload(string Signature, string? KeyId);
+
+public interface IVexSigner
+{
+    ValueTask<VexSignedPayload> SignAsync(ReadOnlyMemory<byte> payload, CancellationToken cancellationToken);
+}