Function init_observability 

pub fn init_observability(log_level: &str) -> PrometheusHandle

Initialises JSON tracing and the Prometheus metrics recorder.

Call once at process startup before any metrics or tracing macros are invoked. Returns the Prometheus render handle used by the /metrics HTTP handler.

Args:

• log_level: Fallback log level (e.g. "info"). Overridden by RUST_LOG.

Usage:

let handle = std::sync::Arc::new(auths_telemetry::init_observability("info"));