Add app/infra/ package with:
- storage/ - repository adapters for runs, run_events, thread_meta
- run_events/ - JSONL-based event store with factory
- stream_bridge/ - memory and redis adapters for SSE streaming
This layer provides the persistence abstractions used by the gateway
services, replacing the old deerflow/persistence modules.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
