feat: Add unit tests

[KCGD]

This PR adds:

• Jest (and ts-jest, @types/jest) dev dependencies
• Test command (via bun run test or bun jest)
• An initial unit test for src/renderer/utils/bus.ts (in tests/renderer/utils/bus.test.ts)

Currently, tests are stored in the /tests directory, which mirrors /src with corresponding unit test files, using naming convention: <file name>.test.ts.

So far I have tested:

• Fresh installation of windows
• Winboat configuration
• Use of standard windows programs
• Use of shared folders
  and noticed no errors.

I have tried using bun's built-in testing suite, but ran into some issues regarding the features it offers.
If bun's built-in suite is preferred, it is viable but will take some adjustments.

[KCGD]

I am incrementally adding unit tests on my own fork, but this PR is ready for discussion whenever.

[KCGD]

As of right now I'll commit per-test, so the PR should always be in a mergeable state. If there are any changes you would like me to make please reach out and I'll adapt my branch. Otherwise, I'll continue adding tests - I am mainly focusing on the renderer utils until those are complete.

Excited to contribute to this awesome project! :)