Add selectResultByKey and selectResultByKeys

[tadfisher]

These might be useful to avoid returning stale entries if we are selecting by key.

[Copilot]

Pull Request Overview

This PR adds two new methods to the KeyValueStorage class to enable efficient key-based selection while returning metadata-rich ResultRow objects instead of just the entity values.

• Adds selectResultByKey() for single key selection returning a ResultRow<T>?
• Adds selectResultByKeys() for multiple key selection with optional ordering and expiration filtering
• Both methods leverage indexed key lookups for better performance compared to where clause queries

Comments suppressed due to low confidence (1)

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