chore: migrate from jest to vitest, eliminate glob@7/inflight deprecations

Replace jest + ts-jest with vitest across all npm repos. jest@29 has a hard
internal dependency on glob@7 (via @jest/reporters, jest-config, jest-runtime)
that cannot be overridden. vitest uses no glob@7 dependency, eliminating the
inflight@1.0.6 and glob@7.2.3 deprecation warnings entirely.

Changes:
- Remove jest, ts-jest, @types/jest from devDependencies
- Add vitest@^3.0.0 as devDep
- Replace jest.config.{js,cjs} with vitest.config.ts
- Update test script: jest -> vitest run
- Replace jest.fn/mock/spyOn/restoreAllMocks -> vi.fn/mock/spyOn/restoreAllMocks
- Replace jest.Mock/Mocked/MockedClass types with vitest equivalents
- Fix ISPConfigClient instantiation to lazy init in beforeAll (pre-existing bug)

All tests pass: zero deprecated warnings on npm install.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: homeofe