v3.139.0

• Reworked the spans package to follow OpenTelemetry semantic conventions: the emitted span tree now uses ydb.* names (ydb.CreateSession, ydb.ExecuteQuery, ydb.BeginTransaction, ydb.Commit, ydb.Rollback, ydb.GetSession, ydb.Driver.Initialize, ydb.RunWithRetry, ydb.Try) and OTel attribute keys (db.*, server.*, network.peer.*, error.*) plus YDB-specific ydb.node.id, ydb.node.dc and ydb.retry.backoff_ms. Noisy internal-package spans are suppressed. See SPANS.md for the full span/attribute reference and migration notes
• Added trace.Retry.OnRetryAttempt callback fired once per retry attempt with the attempt number and the backoff duration waited before it; this is what feeds the new ydb.Try spans
• Added an examples/opentelemetry example that wires spans.Adapter onto the OpenTelemetry Go SDK via ydb-go-sdk-otel, with an end-to-end docker-compose stack (OTel Collector / Tempo / Prometheus / Grafana)

Full Changelog: v3.138.4...v3.139.0