WorkbenchEventMiddleware

Turns agent progress into shared-state frames while the run is still streaming.

Three things happen here, and each of them is what makes a panel in the browser move:

• Seeding — the state object and the context entries the client sent with the run are folded into the thread's WorkbenchState, so shared state is genuinely bidirectional instead of server-push only.

• Task mirroring — after every tool result the live AgentState.getTasksContext() task list (maintained by the built-in todo_write tool) is diffed into shared state, which is how the plan board updates mid-run rather than at the end.

• Permission auditing — RequireUserConfirmEvent and UserConfirmResultEvent are recorded so the audit panel shows the full ask → decide trail. The interrupt itself is emitted by the framework's own lifecycle converter.

Queued CustomEvents are spliced into the event stream around each upstream event. Ordering matters: the opening snapshot goes out immediately after AgentStartEvent so it lands behind RUN_STARTED, open steps are closed and everything still queued is flushed before AgentEndEvent so every STEP_STARTED has a matching STEP_FINISHED and nothing arrives after RUN_FINISHED.