chore: release 0.2.1

[D3ller]

Merge develop into main for the 0.2.1 release.

• test: add vitest non-regression test suite #3 test: add vitest non-regression test suite
• build: add eslint and move to typescript 6 #4 build: add eslint and move to typescript 6
• style: apply eslint rules #5 style: apply eslint rules
• build: add husky hooks to lint on commit and test on push #6 build: add husky hooks to lint on commit and test on push
• ci: run lint, typecheck and tests on main #7 ci: run lint, typecheck and tests on main
• chore: release 0.2.1 #8 chore: release 0.2.1
• build: pin vitest to 5.0.4 to satisfy the release age policy #10 build: pin vitest to 5.0.4 to satisfy the release age policy