fix: update algorithm entry in CoseEcPublicKey to use dynamic value instead of hardcoded constant; improve clarity in CoseEdDsaPublicKeyTests

Author: DennisDyallo

Yubico.YubiKey/src/Yubico/YubiKey/Fido2/Cose/CoseEcPublicKey.cs

@@ -295,8 +295,7 @@ public override byte[] Encode()
 
             return new CborMapWriter<int>()
                 .Entry(TagKeyType, (int)CoseKeyType.Ec2)
-                // .Entry(TagAlgorithm, (int)Algorithm) // Should be correct, right? Instead of hardcoding -25
-                .Entry(TagAlgorithm, (int)CoseAlgorithmIdentifier.ECDHwHKDF256)
+                .Entry(TagAlgorithm, (int)Algorithm)
                 .Entry(TagCurve, (int)Curve)
                 .Entry(TagX, XCoordinate)
                 .Entry(TagY, YCoordinate)

Yubico.YubiKey/tests/unit/Yubico/YubiKey/Fido2/Cose/CoseEdDsaPublicKeyTests.cs

@@ -22,8 +22,9 @@ public class CoseEdDsaPublicKeyTests
             .Replace("-----BEGIN PUBLIC KEY-----", "")
             .Replace("-----END PUBLIC KEY-----", "")
             .Replace("\n", "")
-            .Trim()
-        ).Skip(12).ToArray(); // Skip the COSE key header and extract the public key data
+            .Trim())
+        .Skip(12) // Skip the ASN.1 metadata bytes and keep only the public key data (32 bytes)
+        .ToArray(); 
 
         [Fact]
         public void CreateFromPublicKeyData_ValidKey_ReturnsExpectedKey()