Use ESLint with strict configuration

Configure ESLint with recommended rules:
```json
{
"extends": [
"eslint:recommended",
"plugin:@typescript-eslint/recommended",
"plugin:@typescript-eslint/recommended-requiring-type-checking"
],
"rules": {
"@typescript-eslint/no-unused-vars": "error",
"@typescript-eslint/no-explicit-any": "error",
"no-console": "warn"
}
}
```

Run ESLint in CI and pre-commit hooks.