[heli-os]

Summary

Clarify that implementing UsageProvider and registering it are the core entry points, not a two-file limit. The English, Korean, and Japanese contribution guides now mention source readers, shared caches, custom scan roots, and tests, and link to the existing extension guide and #115. The extension guide uses the same wording.

The three contribution guides also document the existing CI commands: swift build and ./scripts/test-gate.sh, including the default 75% logic-core line-coverage floor.

Type of change

• Bug fix
• New feature
• Refactor / cleanup
• Documentation
• Other:

Validation

• Checked the instructions against .github/workflows/ci.yml, scripts/test-gate.sh, the existing provider/cache/root integration points, and Add support for a new AI coding agent (usage provider) — architecture & contribution guide #115.
• Verified the changed guidance agrees across all three languages and checked relative Markdown link targets.
• git diff --check passed.
• Documentation-only change; no runtime tests added or run locally for this branch.
• GitHub CI passed both build-test (build, full tests, and coverage gate) and secret-scan: https://github.com/chattymin/PokeTokenBar/actions/runs/36311932678

Checklist

• swift build and swift test pass locally
• PR title and description are written in English
• No copyrighted assets, secrets, or private tooling references are committed
• Tests were added or updated for this change