chore(deps): upgrade or remove netlify-cli to clear install deprecations

Summary

netlify-cli@2.71.0 (devDependency) is the root of a large cluster of npm warn deprecated messages on install, including:

• statsd-client, sourcemap-codec, rollup-plugin-inject, rollup-plugin-terser
• netlify-plugin-deploy-preview-commenting, node-pre-gyp, tar@4/tar@6, osenv
• npmlog / are-we-there-yet / gauge
• moize@5 / moize@6
• cli-ux and legacy @oclif/* packages

Parent inventory: #445 (Cluster A).

Options (pick one path)

1. Preferred with hosting migration (#416): remove netlify-cli from the repo once deploys run on Vercel (and drop Netlify-only scripts/config usage).
2. Interim: upgrade netlify-cli to a current major that no longer pulls these packages, and regenerate the lockfile with Node 18 + npm install --legacy-peer-deps.
3. If unused in CI/local workflow: remove it immediately even before #416 completes (verify no scripts/netlify.toml hooks require the CLI locally).

Acceptance criteria

• Decide remove vs upgrade (document choice in a PR)
• After change, Cluster A warnings from #445 no longer appear on a clean install
• Document any remaining Netlify CLI usage (or confirm none)

Related

• #416 Migrate hosting from Netlify to Vercel
• #445 Inventory of npm deprecation warnings

Start by checking the package manifest, repository scripts, and netlify.toml for current netlify-cli usage, then review the hosting migration context in #416. Choose removal or upgrade, regenerate the lockfile as needed with Node 18 and npm install --legacy-peer-deps, and verify a clean install no longer emits the Cluster A warnings.