feat(cybersecurity): auto-commit con 48 cambios

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

functions/cybersecurity/sign_ed25519.go

@@ -0,0 +1,10 @@
+package cybersecurity
+
+import "crypto/ed25519"
+
+// SignEd25519 signs msg with an Ed25519 private key and returns the 64-byte signature.
+// priv must be a valid Ed25519 private key (64 bytes as returned by GenerateIdentity or ed25519.GenerateKey).
+// This function is pure: same inputs always produce the same output (ed25519 is deterministic).
+func SignEd25519(priv, msg []byte) []byte {
+	return ed25519.Sign(ed25519.PrivateKey(priv), msg)
+}