tfrizzell
### Overview This issue tracks the migration of our test runner from Jest to Vitest and the transition from Yarn (Classic) to pnpm. This modernization effort aims to improve development velocity, reduce disk usage, and provide a more performant testing environment. ### Migration Tasks **Migration** - [ ] Migrate from Yarn Classic to pnpm - [ ] Migrate from Jest to Vitest **Validation** - [ ] Ensure all existing tests pass under Vitest with no functional regressions - [ ] Ensure Gulp tasks run correctly under pnpm - [ ] Ensure the extension builds correctly under pnpm - [ ] Update GitHub Actions to use pnpm and Vitest ### Why this is needed * **Performance:** Vitest provides near-instant watch mode and faster execution. * **Efficiency:** pnpm uses content-addressable storage, significantly reducing duplicate packages and installation times. * **Maintenance:** Moving away from deprecated Yarn v1 and Jest legacy configuration simplifies our dependency tree.