- Add sirupsen/logrus v1.9.4 dependency to go.mod
- Add logging package with global Logger instance
- Add Config struct with Level, Format, and Output fields
- Add DefaultConfig with LOG_LEVEL, LOG_FORMAT, and LOG_OUTPUT environment variables
- Add Init function with level parsing, JSON/text formatter selection, and stdout/stderr output
- Add InitWithDefaults helper function
- Add WithField, WithFields, and WithError helper
