When CrewAI is initialized from a non-main thread (e.g., in Streamlit,
Flask, Django, Jupyter), the telemetry module was printing multiple
ValueError tracebacks for each signal handler registration attempt.
This fix adds a proactive main thread check in _register_shutdown_handlers()
before attempting signal registration. If not in the main thread, a debug
message is logged and signal handler registration is skipped.
Fixes#4289
Co-Authored-By: João <joao@crewai.com>
9af03058fe