Hermes Telemetry v0.3.0

Added

• Cross-harness trace correlation, both directions. A tool that launches another agent can pass it the current tool span with child_env() (or current_traceparent()), so the child harness's spans land under that tool call in one trace instead of in a trace of their own — the causal edge a shared session id alone cannot express. LATITUDE_HERMES_EXPORT_TRACEPARENT=1 scopes those variables onto os.environ around each tool call instead, so any subprocess inherits them with no code change; it is off by default because os.environ is process-wide while Hermes runs each turn on its own thread. In reverse, a Hermes process launched with a TRACEPARENT joins that trace and reports the inherited LATITUDE_SESSION_ID, keeping its own session id under hermes.session.id (LATITUDE_HERMES_INHERIT_CONTEXT=0 opts out). Joining is capped per process so a long-lived agent cannot grow a trace it does not own without bound. The active span is published under both TRACEPARENT and LATITUDE_TRACEPARENT, since reads prefer the scoped name and a chained parent's header would otherwise outrank it. Contract: dev-docs/trace-correlation.md.