Add Remote session foundations and feasibility checks

Add opt-in Tentacle protocol 1.1, explicit remote grants, lifecycle IPC and expiring core leases in both SDKs. Revoke access before update preparation, including failed updates.

Add transient secret entries, shared Braille cell export and isolated Xorg recovery experiments with focused tests and documented limitations. Production consent, desktop services and live interoperability remain pending.

internal/tentacle/protocol.go

@@ -145,7 +145,11 @@ func valid_id(value string) bool {
 }
 
 func validate_registration(registration Registration, session string) error {
-	if registration.Protocol != (Version{Major: 1, Minor: 0}) || registration.Session != session ||
+	return validate_registration_version(registration, session, Version{Major: 1, Minor: 0})
+}
+
+func validate_registration_version(registration Registration, session string, version Version) error {
+	if registration.Protocol != version || registration.Session != session ||
 		len(registration.Commands) == 0 || len(registration.Commands) > MaxCommands {
 		return ErrProtocol
 	}