remove unused libraries

[wintonzheng]

[!IMPORTANT] Remove unused libraries, update dependencies, and delete deprecated visualizer feature.

• Dependencies:
  • Removed unused libraries colorlog and chromadb from pyproject.toml.
  • Added posthog and aiofiles to pyproject.toml.
• File Deletions:
  • Deleted streamlit_app/visualizer/__init__.py, api.py, artifact_loader.py, repository.py, sample_data.py, streamlit.py, and styles.py to remove the visualizer feature.
  • Deleted entrypoint-streamlit.sh.
• Code Cleanup:
  • Removed deprecated comments in actions.py and handler.py.

^{This description was created by for 7071eba984546221e05523b2e3d7f33ac06de5ea. It will automatically update as commits are pushed.}