Feishu streaming cards auto-close after 10 minutes from creation,
regardless of update activity. With resuming enabled, a single card
lives across multiple tool-call rounds and can exceed this limit,
causing the final response to be silently lost.
Remove the _resuming logic from send_delta so each tool-call round
gets its own short-lived streaming card (well under 10 min). Add a
fallback that sends a regular interactive card when the final
streaming update fails.