Unify generators into cortex spawning system
Refactor generate.py to use NDJSON protocol like agents, spawned by
cortex rather than standalone CLI. Key changes:
- generate.py: Remove argparse CLI, add NDJSON stdin mode with event
emission (start/finish/error). Remove dead count_tokens function.
- cortex.py: Add routing logic (tools→agents, output→generators) and
consolidate _spawn_agent/_spawn_generator into shared _spawn_subprocess
- dream.py: Run generators via cortex_request sequentially using
wait_for_agents utility
- importer.py: Use cortex_request for import summaries
- models.py: Add generate_with_result to __all__ exports
- docs: Fix stale -c flag reference and CallosumConnection API example
- tests: Update for NDJSON protocol, add test_spawn_generator
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>