Add LongHorizon-Harness tool example

[Upper9527]

What changed

• Add a LongHorizon-Harness tool-mapping page under examples/.
• Link the page from the examples tool index.

Why

The new page maps the repository's six loop primitives to LongHorizon-Harness's Manager / Executor / Auditor lifecycle and durable verified state. It also gives a minimal CLI run, explains where external scheduling and worktree isolation are still needed, and links back to this repository's safety gates.

This is a tool example rather than a new pattern: it does not change the registry or claim pattern coverage that has not been implemented.

Validation

• Checked the commands and state paths against the current LongHorizon-Harness README.
• Confirmed the local safety link resolves and the upstream project is public and active.
• Ran git diff --check; this is the content-only contribution path described in CONTRIBUTING.md.
• Searched open and closed issues and pull requests for an existing LongHorizon-Harness entry.

[github-actions]

Thanks @Upper9527 for contributing a tool example — visible, reviewable PRs like this grow the reference for everyone.

What happens next

• Maintainer aims for same-day review on story, adopter, and scoped docs/example PRs (CONTRIBUTING.md).
• good first issue PRs: comment on the linked issue so we can assign and close on merge.

More ways to help

• Contributor quickstart + open issues
• Good first issue backlog

— loop-engineering maintainers

[Upper9527]

Closing this draft PR because I am switching to an issue-first discussion. I will open a concise issue with the project context so maintainers can decide whether this tool mapping fits before any documentation change. Thanks.