feat:added gitTreeMatch for cross workflow gate reuse

[Ishaan Kesarwani (IshaanXCoder)]

Pull Request

Summary

What changed:

Adds gitTreeMatch to src/git-tree-match.ts, which compares the current git tree hash for a repo-relative path against recent successful gh actions workflow runs on a branch and re-exports it(plus GitTreeMatchOptions, GitTreeMatchResult, WorkflowRunInfo) from src/action-runtime.ts.

Why:
issue described entirely in #23

Important

Keep reviewed diffs small. If this adds more than 500 lines outside generated files or lockfiles, split it.
(604, kept it in a single only, lmk if we need to split it)

Lines added, excluding generated files and lockfiles: -> 604

Test Plan

• CLA/Vouch check passes, or this PR only updates VOUCHED.td
• npm run lint
• npm run typecheck
• npm test
• npm run build
• npm run check
• npm run package

Generated Output

N/A

Release Impact

• Runtime/library behavior changed
• CLI behavior changed
• Generated YAML changed
• Package contents changed
• Documentation only
• N/A

Compatibility

N/A

Changelog

[2026-07-13]

Feedback received:

• (none yet)

Changes made:

• Initial implementation

[Ishaan Kesarwani (IshaanXCoder)]

Windsor Nguyễn (@windsornguyen) review this whenever you get some time, lmk if we need any changes :)