feat: add HistoryProcessors wrapper

[Wh1isper]

closes #2095

[hyperlint-ai]

PR Change Summary

Added a new wrapper for HistoryProcessors to modify message history in the agent, allowing for enhanced memory management and privacy features.

• Introduced HistoryProcessors wrapper for modifying message history
• Enabled option to replace original conversation history
• Provided examples for managing message history with custom processors

Modified Files

• docs/message-history.md

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