Decide where harness-specific agent configuration lives

### Feature Request / Improvement

Decide whether harness-specific agent configuration belongs in the XTable repository, and if so under what rules.

## Why this needs a decision

PR #829 adds `.claude/skills/xtable-converter/` with a `SKILL.md`, scripts, references and an evals file, plus a repo-level `.claude/settings.json`. The underlying work is valuable. The question is where it lives.

Two things are worth separating:

- The **harness-neutral** parts, meaning the config schema, the troubleshooting taxonomy, the verifier and the output parser. These are the tool layer, and they belong in the project regardless of which agent is in front of them.
- The **harness-specific** wrapper, which only works for one product.

## What a sibling project decided

`apache/hudi` has no `CLAUDE.md`, `AGENTS.md`, `SKILL.md`, `.claude/` or `.cursor/` anywhere in the repository. Their agent work is a neutral service exposing MCP. That is a data point, not a rule, but it is worth weighing.

## Questions to settle

1. Do harness-specific files belong in an ASF repository at all, or should the project ship a documented CLI contract plus an MCP server and let wrappers live elsewhere, for example in a plugin marketplace?
2. If they do live here, how are they handled at release time: excluded from the source release, or accounted for in LICENSE and NOTICE?
3. How are they kept from rotting? A skill that describes the config schema in prose starts lying the moment the schema changes. PR #829 includes an `evals.json`, which is the right instinct but is not wired into CI.
4. A repo-level settings file that grants tool permissions applies to **every** contributor who clones the repository. That needs explicit consensus on its own, separate from whether the feature is wanted.

This should be settled on dev@ rather than as a side effect of merging a feature PR.

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

Review PR #829, especially .claude/skills/xtable-converter/, SKILL.md, evals.json, and .claude/settings.json, then compare the repository state with the apache/hudi example. Bring the repository-placement, release licensing, freshness, CI, and permissions questions to dev@; done means the project has a documented consensus and policy.

Written by the indexing model from the issue text.