ConstReadonlyConsoleTransport: symbolIndividual transport tokens (for factory registration)
ReadonlyFormatter: symbolLog formatter (JSON or Pretty)
ReadonlyLoggerService: symbolMain logger service facade
ReadonlyLogLevelOptions: symbolConfigured log level for filtering
ReadonlyTransports: symbolArray of active transports
Dependency Injection Tokens for Logger Module
Symbol-based tokens ensure type-safe dependency injection and prevent naming collisions.