v0.52.0

Added

• Added a Vitest unit-test layer, colocated as *.test.ts next to each module: pure lib/ logic (validation, pagination, EAT formatting, upload-error classification, lyrics parsing, constants helpers, rate-limit's client-IP resolution, media bucket-URL routing) and, via a mocked prisma/getSession, the invite/role-gating RBAC guard (last-active-admin and self-demotion checks) factored out of member-actions.ts into a new member-guards.ts module. Wired npm run test into a new unit.yml required check, and fixed a pre-existing gap where e2e wasn't actually enforced as a required status check on main. (closes #139)