Add tests

[Nitish-bot]

As L5 grows, it’s going to become harder to ensure that new changes aren’t breaking existing functionality. Since we currently have no automated tests, we're essentially "flying blind" on regressions. I am thinking of two testing strategies that make sense for L5.

1. Unit Testing: We need a way to verify that individual functions like math and state management behave as expected.

2. Visual Regression / Example Runner: Since this is a processing-like repo, the most important output is the canvas. A unit test can’t easily tell if a circle is being rendered with the wrong offset.
   In essence we need the test runner to execute a subset of the scripts in /examples (only deterministic examples that have the same output on every run), captures the frame buffer, and compares it against a "Golden Master" (a known good reference image).

As for the testing framework, I have not delved deep into so take this with a grain of salt but I think busted is a strong choice. It says it's a unit-tester but really it can be used as an orchestrator. This way one framework can be used for both testing strategies.