feat(cache): Implement threaded stream finalization

[devin-ai-integration]

This PR implements threaded stream finalization to improve performance for sources with many streams and provide better resilience against process interruptions.

Changes:

• Add ThreadPoolExecutor for concurrent stream finalization
• Finalize each stream in a separate thread as it completes
• Add configurable maximum thread count setting
• Make relevant components thread-safe
• Add locks to prevent concurrent state message commits
• Implement proper thread cleanup

Requested by: Aaron (AJ) Steers (Aaron ("AJ") Steers (@aaronsteers))
Link to Devin run: https://app.devin.ai/sessions/9aebdd8a2c98418aaa4f1ec281c89574

[devin-ai-integration]

🤖 Devin AI Engineer

Original prompt from Aaron:

@Devin - Can you take a look at PyAirbyte and see if you can update it to begin write/commit/finalize each stream into the cache, within a new thread as it finishes reading?

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[devin-ai-integration]

Closing due to inactivity for more than 7 days.