chore: adapt eslint config for eslint 9 compatibility
Fresh yarn install resolved eslint ^9.35.0 to v9, which requires flat config (eslint.config.js) by default. Instead of migrating the entire config, use ESLINT_USE_FLAT_CONFIG=false to keep the existing .eslintrc.js. Also disable two new rules from the updated @typescript-eslint plugin that would require source code changes: - no-require-imports: new rule that flags require() calls - no-unused-vars caughtErrors: now flags unused catch variables