AutoFlow CLI: stream workflow logs to the client
Follow-up from !3973 (merged) (Follow-ups: module-developer debuggability).
The autoflow CLI is a thin client over the AutoFlow API. GetWorkflow returns only the workflow state plus a terminal result, so a flow's print() output and step-by-step progress go to the server's (Relay/GDK) logs, never to the client. run therefore can't show live output, and there is no logs -f.
Add a server-side streaming RPC (e.g. StreamWorkflowLogs, or streamed workflow history events) and a client logs [-f] <workflow-key> command; have run (without --detach) stream output live instead of only polling state.
Notes
Requires a new RPC in internal/module/autoflow/rpc (add-only, backwards-compatible), server plumbing, and the engine exposing history/print events. This is the largest of the three debuggability follow-ups.
Acceptance criteria
autoflow logs -f <key>streamsprint()output and state transitions until terminal.runshows live output.