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()