feat : add ESLint linter to frontend with pre-commit hook

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>

pre-commit

@@ -24,6 +24,16 @@ else
 fi
 echo "--- php-cs-fixer pre commit hook finish---"
 
+echo "--- eslint pre commit hook start ---"
+make nuxt-lint
+ESLINT_RESULT=$?
+
+if [ $ESLINT_RESULT -ne 0 ]; then
+    echo "ESLint failed. Aborting commit."
+    exit 1
+fi
+echo "--- eslint pre commit hook finished ---"
+
 echo "--- phpunit pre commit hook start ---"
 make test
 PHPUNIT_RESULT=$?