Observability

Read in this order:

1. Overview: choose between Event Center, TriggerFlow runtime stream, DevTools, and coding-agent guidance.
2. Event Center: framework-level observation events and compatibility rules.
3. DevTools: observation bridge, evaluation bridge, and interactive wrappers.

Observation events observe what happened. TriggerFlow emit / when changes flow control, and TriggerFlow runtime stream sends live data to consumers.