Add pyarrow to base Docker image dependencies

[Copilot]

The container image did not include pyarrow, requiring manual installation after startup. This change bakes pyarrow into the image so all environments built from the repo have it available by default.

• Dependency installation

  • Added a dedicated pip install pyarrow layer to the root Dockerfile before installing the project package.

• Build behavior

  • Keeps the existing image flow unchanged (pip upgrade, repo copy, pip install /app/PerTurbo) while ensuring pyarrow is present in the runtime environment.

RUN pip install --upgrade pip
RUN pip install pyarrow
...
RUN pip install /app/PerTurbo