[heft-jest-plugin] Migrate from @types/heft-jest to @types/jest

[iclanton]

Summary

Projects in this repo previously used a custom @types/heft-jest type shim for Jest typings, and heft-jest-plugin injected a mocked() global via a jest-global-setup setupFiles entry. Now that @types/jest correctly includes the mocking typings and Jest 30 ships jest.mocked() as the standard API, the shim and workaround are no longer needed.

Changes:

• Replace @types/heft-jest with @types/jest in all rigs, build tests, samples, and tsconfig.json files
• Remove jest-global-setup.ts from heft-jest-plugin and its setupFiles config entry
• Add @types/jest as an optional peer dependency of heft-jest-plugin

Details

The jest-global-setup script was registered as a Jest setupFiles entry and injected mocked() as a global function, because the old @types/heft-jest shim declared it that way. With Jest 30, jest.mocked() is the idiomatic API, so the global injection is nonstandard and the shim is no longer needed. The official @types/jest package (from DefinitelyTyped) provides the correct typings.

This change does not break backwards compatibility for tests that already use jest.mocked(). Tests using a bare mocked() global will need to update to jest.mocked().

How it was tested

Ran rush build and rush test locally across affected packages.

Impacted documentation

None — the @types/heft-jest shim was an implementation detail not covered in public docs.