Use protopiler for protocol buffers

Co-authored-by: Jamie Kyle <jamie@signal.org>

ts/util/isKnownProtoEnumMember.std.ts

@@ -0,0 +1,9 @@
+// Copyright 2026 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+export function isKnownProtoEnumMember<E extends number>(
+  enum_: Record<string | `${E}`, E | string>,
+  value: unknown
+): value is E {
+  return typeof value === 'number' && Object.hasOwn(enum_, value);
+}