Telemetry integration for the stepwise engine.

All engine lifecycle phases emit :telemetry span events (:start, :stop, :exception suffixes).

Engine spans

• [:mobus_stepwise, :engine, :init]
• [:mobus_stepwise, :engine, :handle_event]
• [:mobus_stepwise, :engine, :restore]

Pipeline events

• [:mobus_stepwise, :pipeline, :action, :start | :stop | :exception]

Metadata

All events include:

• :execution_id
• :tenant_id
• :current_state
• :meta — the full orchestration metadata map

Engine handle_event spans also include:

• :event — the event name
• :status — outcome (:ok, :wait, :error)

Example

:telemetry.attach(
  "my-handler",
  [:mobus_stepwise, :engine, :handle_event, :stop],
  fn _event, measurements, metadata, _config ->
    Logger.info("Event processed in #{measurements.duration}ns")
  end,
  nil
)