Feature Request: Allow SessionStart hooks to display output to the user

Problem

SessionStart hooks can inject output into Claude's internal context, but there's no way to display a message to the user when a session starts.

Claude cannot initiate a conversation — it only responds to user messages. So even though the hook runs and injects context, the user sees nothing until they send the first message.

Use Case

Displaying a session briefing (branch, sprint, dirty files, recent commits) automatically when Claude Code starts, without requiring the user to type something first.

Current Workaround

Users must send an initial message (e.g., "hi") to trigger Claude's response that includes the briefing injected by the hook.

Proposal

Either:

1. Allow hooks to output directly to the terminal (user-visible), or
2. Add an option for Claude to auto-generate a response after SessionStart hooks complete (e.g., "autoRespond": true)