Scoped to only `no-unused-vars` and `react/jsx-no-useless-fragment` —
the safe subset of --fix-suggestions. Primary changes:
- Remove unused named imports from statements
- Remove unused default/type imports entirely
- Collapse `<><Single/></>` fragments to `<Single/>`
Verified clean: typecheck + format + lint all green.
Apply prettier-compatible formatting across the repo to match the
incoming oxfmt configuration. Mechanical reformat only — no logic
changes. Covers YAML quote normalization, package.json key sorting,
Markdown/TOML formatting, and minor TS whitespace tweaks.