- Added @eslint/js dependency - Updated eslint.config.js for ESLint 9 compatibility - Added required globals (crypto, localStorage, React, etc.) - Fixed unused imports and variables - Disabled sort-imports temporarily - Formatted all files with Prettier
- ServiceError base class with statusCode, message, details - HTTP errors: BadRequest, Unauthorized, Forbidden, NotFound, Conflict, TooManyRequests - 10 tests passing (vitest) - Superset of all 4 service error files in LysnrAI
