#2735 Telemetry bridge attributes a parent run's later method invocations to its nested child run

Summary

The libswamp telemetry bridge (src/libswamp/workflows/telemetry_bridge.ts, observe) sets workflowName and runId from every started event in the stream. A workflow step that runs a nested workflow forwards the child's started event into the parent's stream. So after a nested step starts, every method invocation the bridge records, including ones from the parent's later steps, is attributed to the child's workflow name and run id.

Context

Found while fixing swamp-club#2470. Nested started events now carry parentRunId, so the bridge can tell them apart. The fix needs a decision on attribution: record child steps under the child run (the bridge would need a per-run stack), or record everything under the top-level run.

Steps to reproduce

1. Workflow child with one model_method step. Workflow parent with a workflow step running child, followed by a model_method step.
2. Run parent with telemetry enabled.
3. The parent's second step invocation is reported with the child's workflowName and runId.