chore: migrate Jest to Vitest

[nclsndr]

What does it do?

Migrate Jest to Vitest.
Change package.json script name: test:cov -> test:coverage

Why is it needed?

Future proofing the codebase with very little implementation overhead.

How to test it?

pnpm run test
pnpm run test:coverage

[nclsndr]

Perf improvements:

Jest

Test Suites: 23 passed, 23 total
Tests:       336 passed, 336 total
Snapshots:   0 total
Time:        9.204 s

Source

Vitest

 Test Files  23 passed (23)
      Tests  333 passed (333)
   Start at  14:41:49
   Duration  2.60s (transform 1.11s, setup 0ms, collect 3.10s, tests 708ms, environment 5ms, prepare 173ms)

Source

[nclsndr]

Waiting for #106 to merge first