Add a top-level Hunk version command

[benvinegar]

Summary

• add hunk --version, hunk -v, and hunk version
• resolve the packaged version from the shipped manifest instead of hardcoding it
• cover both parser and spawned-CLI version output in tests

Why

We needed an easy way to verify which Hunk build is actually running after beta installs, especially while testing the new prebuilt npm release flow.

What changed

• src/core/cli.ts
  • adds version resolution from nearby package.json
  • handles top-level --version, -v, and version
  • advertises -v, --version in the help text
• test/cli.test.ts
  • verifies top-level version parsing
• test/help-output.test.ts
  • verifies the spawned CLI prints only the version string without terminal takeover sequences

Validation

• bun run typecheck
• bun test test/cli.test.ts test/help-output.test.ts