refactor(tests): split ChargingStation.test.ts into domain files

refactor(tests): split ChargingStation.test.ts into domain files

Split monolithic 2587-line test file into focused domain files:
- ChargingStation-Lifecycle.test.ts (225 lines) - start/stop/restart
- ChargingStation-Connectors.test.ts (578 lines) - connector ops
- ChargingStation-Transactions.test.ts (619 lines) - transaction handling
- ChargingStation-Configuration.test.ts (777 lines) - config management
- ChargingStation.test.ts (250 lines) - integration tests only

Total: 2449 lines across 5 files (was 2587 in 1 file)
All 268 tests passing