Release 1.47.0

[carlosalberto]

July 2025 release.

Context

• Add Supplementary Guidelines for environment variables as context carrier
  specification.
  (#4548)

Traces

• Define sampling threshold field in OpenTelemetry TraceState; define the behavior
  of TraceIdRatioBased sampler in terms of W3C Trace Context Level 2 randomness.
  (#4166)
• Define CompositeSampler implementation and built-in ComposableSampler interfaces.
  (#4466)
• Define how SDK implements Tracer.Enabled.
  (#4537)

Logs

• Stabilize Event Name parameter of Logger.Enabled.
  (#4534)
• Stabilize SDK and No-Op Logger.Enabled.
  (#4536)
• SeverityNumber=0 MAY be used to represent an unspecified value.
  (#4535)

Baggage

• Add Supplementary Guidelines for environment variables as context carrier
  specification.
  (#4548)

Compatibility

• Clarify expectations about Prometheus content negotiation for metric names.
  (#4543)

[pellared]

How about also adding #4552 to the release as it would play well together with #4535?

[carlosalberto]

@pellared Actually moved it its very own "Supplementary guidelines" section (where it makes more sense).