build(test-potel-trace-propagation): Migrate backend from pip to uv

[ericapisani]

Summary

• Replace backend/requirements.txt with backend/pyproject.toml for dependency management
• Update backend/run.sh to use uv run instead of manual venv/pip workflow
• Only the backend subdirectory is Python; frontend/webservice are unaffected
• Part of PY-2428 migration effort

Test plan

• Run cd backend && ./run.sh and verify the Flask app starts correctly

🤖 Generated with Claude Code

[linear-code]

PY-2486

PY-2428

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[cursor]

Installed uv not in PATH for current session

High Severity

When uv is not installed and the curl | sh installer runs, it modifies shell profile files (.bashrc, .zshrc, etc.) to add uv to PATH. Those profile changes only take effect in new shell sessions, not the current one. So when execution reaches uv run flask --app main run immediately after, the shell still can't find uv and the script fails with a "command not found" error.

 

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