Restructure solution layout by module

src/__Libraries/StellaOps.Cryptography/ICryptoSigner.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.IdentityModel.Tokens;
+
+namespace StellaOps.Cryptography;
+
+/// <summary>
+/// Represents an asymmetric signer capable of producing and verifying detached signatures.
+/// </summary>
+public interface ICryptoSigner
+{
+    /// <summary>
+    /// Gets the key identifier associated with this signer.
+    /// </summary>
+    string KeyId { get; }
+
+    /// <summary>
+    /// Gets the signing algorithm identifier (e.g., ES256).
+    /// </summary>
+    string AlgorithmId { get; }
+
+    /// <summary>
+    /// Signs the supplied payload bytes.
+    /// </summary>
+    /// <param name="data">Payload to sign.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>Signature bytes.</returns>
+    ValueTask<byte[]> SignAsync(ReadOnlyMemory<byte> data, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Verifies a previously produced signature over the supplied payload bytes.
+    /// </summary>
+    /// <param name="data">Payload that was signed.</param>
+    /// <param name="signature">Signature to verify.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns><c>true</c> when the signature is valid; otherwise <c>false</c>.</returns>
+    ValueTask<bool> VerifyAsync(ReadOnlyMemory<byte> data, ReadOnlyMemory<byte> signature, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Exports the public representation of the key material as a JSON Web Key (JWK).
+    /// </summary>
+    /// <returns>Public JWK for distribution (no private components).</returns>
+    JsonWebKey ExportPublicJsonWebKey();
+}