test: Add unit tests for a utility in apps/studio/src/shared/lib

Summary Increase coverage and give newcomers a gentle intro to the Jest setup by testing a small, pure utility function.

Where

• apps/studio/src/shared/lib (pick a pure function: formatter, geometry helper, id generator).
• Test config: jest.config.ts at repo root.

Steps

1. Branch: git checkout -b test/shared-lib-util.
2. Choose a small pure function with no side effects.
3. Create a colocated *.test.ts; cover the happy path plus 1–2 edge cases.
4. Run yarn test and confirm it passes.
5. Commit test: add unit tests for <function> and open a PR.

Acceptance criteria

• New test file passes under yarn test.
• At least 3 assertions covering normal + edge cases.

Good first issue — comment here if you'd like to take it.