fix(ocpp2): implement ClearCache and Reset OnIdle fixes per audit (CLR-001, CLR-002...

fix(ocpp2): implement ClearCache and Reset OnIdle fixes per audit (CLR-001, CLR-002, RST-001)

- Override handleRequestClearCache() for OCPP 2.0.1 to use Authorization Cache
- Add AuthCacheEnabled check per C11.FR.04 (return Rejected if disabled)
- Extend Reset OnIdle to check firmware updates and reservations per errata 2.14
- Add comprehensive test coverage for ClearCache spec compliance
- Update base class signature to support async ClearCache in OCPP 2.0.1
- Fix ESLint errors in test file (remove unnecessary conditionals, bind methods)