Add unattended promotion deployment daemon

[LVT-ENG]

Added a new background python daemon scripts/unattended_deploy_routine.py that continuously monitors the promotions/ directory for JSON files, safely avoiding race conditions by checking modification times, and leveraging the existing deploy_promotions.py script to do the structure validation and actual production deployment. Processed files are then moved to success or failure directories accordingly.

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PR created automatically by Jules for task 13380781011629513754 started by @LVT-ENG

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