Module persistence 

Persistence support for @persistent agent beliefs.

This module provides the runtime support for persistent agent state:

• CheckpointStore trait for storage backends
• Persisted<T> wrapper for auto-checkpointing fields
• AgentCheckpoint for managing agent-level persistence

Backends

The following backends are available via feature flags:

• persistence-sqlite: SQLite database (recommended for local development)
• persistence-postgres: PostgreSQL (recommended for production)
• persistence-file: JSON files (useful for debugging)

Without any persistence feature, only MemoryCheckpointStore is available.

Structs

MemoryCheckpointStore

In-memory checkpoint store for testing.

Persisted

A wrapper for @persistent fields that auto-checkpoints on modification.

Traits

CheckpointStore

A checkpoint store for persisting agent state.

Functions

agent_checkpoint_key

Helper to generate a unique checkpoint key for an agent instance.

checkpoint_all

Helper to save all @persistent fields atomically before yield.