EF Core: Implement execution strategy for connection resiliency

[DaveRMaltby]

Summary

The EF Core providers do not register an IExecutionStrategyFactory. This means there is no retry logic for transient failures (e.g., file locked by another process, temporary I/O errors).

What's Needed

1. Custom ExecutionStrategy — detect transient file I/O exceptions (IOException, UnauthorizedAccessException with sharing violations) and retry
2. IExecutionStrategyFactory registration — register with the EF Core DI container
3. Configuration — allow consumers to configure retry count and delay

Why This Matters

File-based storage is susceptible to transient file locking issues, especially on Windows or when files are in synced folders (OneDrive, Dropbox). A retry strategy would make the provider more robust.

Standard Reference

• Connection Resiliency
• IExecutionStrategy