Hey there, thanks for sharing your error and welcome to the Streamlit community! 
This is a common issue when deploying apps that use OpenCV (cv2) on Streamlit Community Cloud. The error ImportError: libgthread-2.0.so.0: cannot open shared object file: No such file or directory means a required system library is missing in the deployment environment.
To fix this, create a file named packages.txt in your repo (at the root, next to requirements.txt) and add the following line to it:
libglib2.0-0
Commit and push this file to your repo, then reboot your app. This will install the missing system dependency and should resolve the error. For more details, see the guidance in the Streamlit docs and community solutions like this one.
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