Tracing disabled when sample rate is zero

OpenTelemetry tracing is completely disabled when tracing.sample_rate is set to 0.0. No traces will be collected or exported regardless of exporter configuration.

To enable tracing, set tracing.sample_rate between 0.0 and 1.0 (e.g., 0.1 for 10% sampling). Value of 1.0 traces all requests. Verify exporter_type is configured (zipkin, jaeger, otlp, or in_memory) and corresponding endpoint settings are valid.