Fix autopilot drive-all loop — agent was stopping after one task

The orchestrator only drove ONE task per invocation, then stopped with
ORCHESTRATION_COMPLETE. User had to manually re-trigger for each task.

Changes:
- Added drive_all() outer loop that scans EVERY task and drives them all
- Tasks needing user review are flagged; orchestrator continues to next
- Only stops when ALL tasks are terminal or ALL remaining need user input
- Output format now shows session summary (completed, awaiting review, blocked)
- Session-starter references 'orchestrate' as primary command
- Updated continue-from-existing to use drive_all()

references/session-starter.md

@@ -20,6 +20,7 @@ After reading these files, acknowledge with: ".agent.md and .rules.md loaded. Re
 1. Start a fresh session with your agent.
 2. Paste the block above (replace `{project}` with the actual path).
 3. Then give your real request, for example:
+   - "orchestrate" — drive ALL remaining tasks to completion
    - "What should we do next on this project?"
    - "Implement the fix-alert-test task"
    - "Onboard this project to the agent framework"