Makefile use venv by default enforce PEP 668

[RubenVP2]

Modern Debian/Ubuntu systems enforce PEP 668, which blocks pip install system-wide to prevent breaking the OS-managed Python environment.

Current OS :

Error :

~/workspace/OpenMontage$ make setup
==> Installing Python dependencies...
pip install -r requirements.txt
error: externally-managed-environment

× This environment is externally managed
╰─> To install Python packages system-wide, try apt install
    python3-xyz, where xyz is the package you are trying to
    install.

    If you wish to install a non-Debian-packaged Python package,
    create a virtual environment using python3 -m venv path/to/venv.
    Then use path/to/venv/bin/python and path/to/venv/bin/pip. Make
    sure you have python3-full installed.

    If you wish to install a non-Debian packaged Python application,
    it may be easiest to use pipx install xyz, which will manage a
    virtual environment for you. Make sure you have pipx installed.

    See /usr/share/doc/python3.13/README.venv for more information.

note: If you believe this is a mistake, please contact your Python installation or OS distribution provider. You can override this, at the risk of breaking your Python installation or OS, by passing --break-system-packages.
hint: See PEP 668 for the detailed specification.
make: *** [Makefile:7: setup] Error 1

Fix: Updated the Makefile to automatically create a .venv virtual environment and use it for all Python operations.

Changes:

• Added VENV, PYTHON, and PIP variables pointing to .venv/bin/
• setup now creates venv if it doesn't exist (python3 -m venv venv) before installing
• All python and pip calls across every target now use the venv binaries
• install, install-dev, install-gpu also auto-create the venv if missing