初版功能完成

internal/overlay/clientwg/key.go

@@ -0,0 +1,20 @@
+package clientwg
+
+import (
+	"encoding/base64"
+	"fmt"
+)
+
+// ParseKeyBase64 parses the standard WireGuard 32-byte base64 key format.
+func ParseKeyBase64(value string) (Key, error) {
+	var key Key
+	decoded, err := base64.StdEncoding.DecodeString(value)
+	if err != nil {
+		return key, fmt.Errorf("decode WireGuard key: %w", err)
+	}
+	if len(decoded) != keySize {
+		return key, fmt.Errorf("WireGuard key decoded length is %d, want %d", len(decoded), keySize)
+	}
+	copy(key[:], decoded)
+	return key, nil
+}