What changed:

Changed three immutable local JSON values in RawRepresentableTests from var to let.

Why:

This removes Swift compiler warnings about variables that are never mutated, without changing test behavior or public API.

Checklist:

• Does this have tests?
• Does this have documentation?
• Does this break the public API (Requires major version bump)?
• Is this a new feature (Requires minor version bump)?

Validation:

• swift test baseline passed before the change: 149 tests
• swift test --filter RawRepresentableTests
• swift build --build-tests
• git diff --check