[Refactor][CI/Docker] Replace poetry with uv for Python package management

[narrowizard]

What and why to refactor

Problem: CI job "build image" fails when installing Poetry via the official installer.

The issue occurs in backend/Dockerfile during the base stage build:

RUN curl -sSL https://install.python-poetry.org | python3 -

which results in:

Installing Poetry (2.3.2): Creating environment
Installing Poetry (2.3.2): Installing Poetry
Installing Poetry (2.3.2): An error occurred. Removing partial environment.
Poetry installation failed.

Why refactor now:

• Poetry installer is unreliable in CI
• Alternative approach (pipx) also has issues

Describe the solution you'd like

Replace poetry with uv, a Rust-based Python package manager:

Advantages:

• 10-100x faster than poetry
• Compatible with pyproject.toml (no config changes needed)
• Minimal overhead in QEMU environments
• Actively maintained by Astral (ruff creators)

Related issues

• Original issue: poetry timeout in CI arm64 builds
• Python 3.9 EOL concerns

Additional context

Root cause identified: Poetry 2.3.x is incompatible with Python 3.9. The installer silently fails because it cannot create a working environment.

Attempted workarounds:

1. curl installer fails - Original method using install.python-poetry.org:

   Installing Poetry (2.3.2): Creating environment
   Installing Poetry (2.3.2): Installing Poetry
   Installing Poetry (2.3.2): An error occurred. Removing partial environment.
   Poetry installation failed.
   

   • Root cause: Poetry 2.3.x requires Python >= 3.10, but the devlake base image uses Python 3.9

2. Version pinning to 2.2.1 - Locking to last Python 3.9 compatible version:

   curl -sSL https://install.python-poetry.org | python3 - --version 2.2.1

   • Installation succeeds with Poetry 2.2.1
   • However, poetry install still times out in CI arm64 builds:

     Creating virtualenv azuredevops-ANnMAkq9-py3.9 in /app/.cache/pypoetry/virtualenvs
     failed to query /usr/local/bin/python3.9 with code -1 err: 'timed out'
     

   • Timeout occurs during virtualenv creation when Poetry queries the Python interpreter
   • This is exacerbated by QEMU emulation in cross-platform CI builds

3. pipx install poetry - Using pipx with version pinning:

• Installation succeeded: python3 -m pipx install poetry
• But poetry install still fails in CI arm64 builds:

  Creating virtualenv azuredevops-ANnMAkq9-py3.9 in /app/.cache/pypoetry/virtualenvs
  failed to query /usr/local/bin/python3.9 with code -1 err: 'timed out'
  

• Root cause: Poetry queries Python interpreter during virtualenv creation, which times out in QEMU-emulated arm64 environments
• Local arm64 builds succeed because they run on native hardware