dsh-otel: Exporting DeepSeek Harness Sessions as OpenTelemetry Spans

dsh-otel is a DeepSeek Harness plugin that translates session logs into OpenTelemetry spans, enabling DSH data to be integrated into existing tracing systems. The plugin is disabled by default and requires manually configuring an exporter; it supports OTLP/HTTP and stdout export. It focuses on one-way data conversion, does not depend on an SDK runtime, and includes only names, IDs, timestamps, token counts, and metadata, making it suitable for developers who need to connect DSH debug data to their existing observability stack.