OPS-6978 Fix OpsLevel checks

[whodeen]

Summary

• Migrate formatter setup from Prettier to Oxfmt.
• Add oxfmt.config.ts using @shelf/prettier-config/oxfmt.
• Move ESLint to the Shelf no-Prettier flat config entrypoint required by the Oxfmt migration.

Validation

• yarn install
• yarn lint
• yarn lint:ci
• yarn type-check
• yarn build

Notes

• No test script is defined in package.json.
• Node emits the expected MODULE_TYPELESS_PACKAGE_JSON warning for oxfmt.config.ts in this CommonJS package; formatting and lint checks pass.
• Build exits successfully with the existing optional aws-crt AWS SDK warning.

Remote CI Blocker

• CircleCI build fails before repo lint/type-check because the generated CircleCI config runs pnpm install --frozen-lockfile, but this repo has no pnpm-lock.yaml. The exact error is ERR_PNPM_NO_LOCKFILE Cannot install with frozen-lockfile because pnpm-lock.yaml is absent.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: c6ce4156ac

ℹ️ About Codex in GitHub

Codex has been enabled to automatically review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

When you sign up for Codex through ChatGPT, Codex can also answer questions or update the PR, like "@codex address that feedback".

[chatgpt-codex-connector]

Raise Node engines for the new ESLint toolchain

This upgrades the lint runner to ESLint 10 while package.json still advertises engines.node as >=16. The published ESLint 10.5.0 package requires ^20.19.0 || ^22.13.0 || >=24, so installs or lint jobs that choose Node 16/18 from the advertised engine range can fail before reaching the migrated config; please raise this package's engines or pin tooling that still supports Node 16. (raw.githubusercontent.com)

Useful? React with 👍 / 👎.