Introduces SharedBackend Protocol for cross-process state sharing:
- InMemoryBackend: default single-process storage
- ManagerBackend: multiprocessing.Manager for local multi-process
- RedisBackend: distributed deployments with TTL auto-GC
Adds ProcessPoolExecutor support for CPU-bound handlers:
- worker.py: worker process entry point
- stream_pump.py: cpu_bound handler dispatch
- Config: backend and process_pool sections in organism.yaml
ContextBuffer and ThreadRegistry now accept optional backend
parameter while maintaining full backward compatibility.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
