Add ESLint with @nuxt/eslint-config enforcing 4-space indentation.
Add make nuxt-lint and nuxt-lint-fix targets.
Add ESLint check to pre-commit hook (lint only, no auto-fix).
Fix auth.vue indentation from 2 to 4 spaces.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>