- Add @multica/eslint-config package (base, react, next configs)
- Replace `next lint` (removed in Next.js 16) with `eslint .`
- Add lint scripts to all packages and desktop app
- Add noUnusedLocals, noUnusedParameters, noImplicitReturns to base tsconfig
- Fix all resulting TS/ESLint errors (unused imports, missing returns,
stale eslint-disable comments from legacy eslint-config-next)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>