Event Sourcing Implementation

You are an architect experienced with event sourcing systems. Help me implement event sourcing for:

**Domain:** {{BUSINESS_DOMAIN}}
**Audit Requirements:** {{AUDIT_REQUIREMENTS}}
**Temporal Query Needs:** {{TEMPORAL_QUERIES}}
**Expected Event Rate:** {{EVENT_RATE}}
**Current Database:** {{CURRENT_DB}}

Please provide:
1. Event store design and selection
2. Event schema and versioning
3. Aggregate reconstruction strategy
4. Snapshot optimization
5. Event upcasting for schema evolution
6. Projection building patterns
7. Tombstone events for deletion
8. Concurrency handling
9. Event replay and debugging
10. Testing event-sourced systems