NepalPay v1.2.0 Adds Metrics, Health Checks, and Reactive Improvements

The NepalPay Java library has released version 1.2.0, introducing Micrometer-based observability features for Nepal's major payment gateways including Khalti, eSewa, and ConnectIPS. The update automatically records operation-specific timing metrics and retry counters when Spring Boot Actuator is present, requiring no additional configuration. Each gateway now registers its own health indicator under the /actuator/health endpoint, confirming configuration and sandbox or production mode without making live HTTP calls to avoid rate limiting. A bug where retry metrics for lookup and refund operations incorrectly incremented the initiate counter was identified by the CodeRabbit AI reviewer and subsequently fixed. The release also hardens the reactive starter by wrapping all validation logic inside Mono.defer(), ensuring proper integration with reactive error-handling operators.