chore(deps): migrate to esm-only @actions packages

[tenthirtyam]

Summary

Upgrade all @actions dependencies to their latest ESM-only major versions and align the TypeScript and test configurations accordingly.

Dependency changes:

- @actions/cache:      ^5.0.5 → ^6.0.0
- @actions/core:       ^2.0.3 → ^3.0.1
- @actions/exec:       ^2.0.0 → ^3.0.0
- @actions/tool-cache: ^3.0.1 → ^4.0.0

tsconfig.json:

• module: CommonJS → ESNext
• moduleResolution: (implicit node10) → bundler Allows TypeScript to natively consume ESM-only packages and emit ESM output consumed by ncc. No "type": "module" required in package.json; ncc bundles the ESM output to a CJS dist.

tsconfig.test.json:

• module: CommonJS (explicit override)
• moduleResolution: Node16
• ignoreDeprecations: "6.0" Keeps ts-jest in CJS mode so Jest manual mocks in mocks/ continue to intercept @actions imports without loading the real ESM packages at test time.

Type

• This is a bug fix.
• This is an enhancement or feature.
• This is a code style/formatting update.
• This is a documentation update.
• This is a refactoring update.
• This is a chore update
• This is something else.
  Please describe:

Breaking Changes?

• Yes, there are breaking changes.
• No, there are no breaking changes.

Test and Documentation

• Tests have been completed.
• Documentation has been added or updated.

Issue References

Additional Information