Add unit and e2e tests

[nyandika]

Have you read the contributing guidelines ? Yea

What is the purpose of your pull request?

• [ ] Bug fix
• [X] New feature

Proposed changes

Adding unit tests using vitest. Codebase already uses vite to build so this should be a straightforward choice Adding e2e tests using playwright. it is feature rich, cross-browser support and supports multiple languages

I have added sample tests for these two

Also added github actions for tests and validation. This will fail as there are several files that violate linting and formatting. These files can be fixed gradually. I chose not to at this time as there are significantly several files to be touched which will render this PR hard to review and out of scope

Warning

Please read these points carefully and answer honestly with an X into all the boxes. Example : [X]

Before submitting a pull request make sure you have:

• [X] Read the guidelines for contributing.
• [X] Wrote some tests.
• [ ] Respected the linting guidelines.

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