chore(deps): upgrade @actions packages to pre-esm versions

[tenthirtyam]

Summary

Upgrades @actions dependencies to the latest versions that remain CommonJS-compatible, stopping one major before the ESM-only releases.

Also bumps the @typescript-eslint plugins to the latest patch.

- @actions/cache:                    ^4.1.0 → ^5.0.5
- @actions/core:                     ^1.11.1 → ^2.0.3
- @actions/exec:                     ^1.1.1  → ^2.0.0
- @actions/tool-cache:               ^2.0.2  → ^3.0.1
- @typescript-eslint/eslint-plugin:  ^8.59.1 → ^8.59.2
- @typescript-eslint/parser:         ^8.59.1 → ^8.59.2

The next major of each package (cache@6, core@3, exec@3, tool-cache@4) is ESM-only and incompatible with the current "module": "CommonJS" tsconfig. ESM migration is deferred to a separate effort.

Also adds the missing getExecOutput export to the @actions/exec mock, which is called in main.ts but was absent from the mock.

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