Persistent state management for conversation threads, messages, and jobs.
The [StateStore] is the primary entry point, backed by a SQLite database and an
append-only JSONL session index file. It provides CRUD operations for:
- Threads — conversation metadata, archival, and session indexing.
- Messages — append-only message storage with tree-structured branching.
- Checkpoints — named state snapshots for restoring conversation progress.
- Jobs — background task tracking with status and progress.
- Dynamic tools — per-thread tool registrations.