docs(service-discovery-types): changelog for optional-param conversion

The converter now emits optional parameters from `MethodSchema.required`;
record that consumer-observable change under the unreleased section.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: grypez

packages/service-discovery-types/CHANGELOG.md

@@ -14,4 +14,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - JSON-serializable API schema vocabulary: `TypeSpec`, `ObjectSpec`, `MethodSpec`, `RemotableSpec`
   - One-way `MethodSchema` → `RemotableSpec` converter (`methodsToRemotableSpec`, `methodSchemaToMethodSpec`) for bridging existing discoverable-exo schemas into the new format
 
+### Changed
+
+- `methodSchemaToMethodSpec` marks any parameter absent from the source `MethodSchema.required` as `optional` on its emitted `ValueSpec`, instead of treating every parameter as required ([#958](https://github.com/MetaMask/ocap-kernel/pull/958))
+
 [Unreleased]: https://github.com/MetaMask/ocap-kernel/