Snapshot Support for Performance

[jwilger]

Overview

Optimize state reconstruction for long-lived streams by periodically saving snapshots and starting reconstruction from snapshot instead of version 0.

Depends on: #247 (Performance Benchmarking Suite) - need performance data to determine if snapshots are necessary and what snapshot frequency makes sense.

Design

SnapshotStore Trait

• save_snapshot(stream_id, version, state) method
• load_snapshot(stream_id) returns (version, state)
• Snapshots stored alongside events
• Automatic snapshot creation at configurable intervals

Executor Integration

• Check for snapshot before reading events
• If snapshot exists, start from snapshot version
• Apply only events after snapshot

Benchmark-Driven

• Use benchmark data to determine optimal snapshot frequency

Acceptance Criteria

• Benchmark data reviewed to determine if snapshots needed
• SnapshotStore trait defined
• Snapshot save/load implemented
• Executor loads from snapshot when available
• Configurable snapshot frequency
• Benchmark documents performance improvement

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Migrated from beads issue: eventcore-012