Make vmnet Python package installable with pip

[nirs]

Make the vmnet Python package installable with pip install -e . to simplify the developer experience. Currently users need to manually create a venv, install dependencies, and source the venv before running scripts.

Current workflow

python3 -m venv .venv
source .venv/bin/activate
pip install pytest scapy pyyaml black
./example server

Proposed workflow

./bootstrap.sh       # creates venv and installs everything (run once)
source venv          # enter the venv (each new terminal)
pytest               # run tests
vmnet run server     # run vm named "server"

bootstap script

python3 -m venv .venv
ln -sf .venv/bin/activate venv
source venv 
pip install -e ".[dev]"

After bootstrap, the user just needs source venv in new terminals, then all tools are available (pytest, vmnet run, vmnet bench).

Changes needed

• Add package metadata and entry points to pyproject.toml
• Add dependency groups (core: pyyaml, dev: pytest scapy black, bench: matplotlib numpy)
• Create a CLI entry point (vmnet) with subcommands (run, bench)
• Update CI to use pip install -e ".[dev]"
• Update README with simplified setup instructions

Benefits

• Single install command sets up everything
• Easier source command
• Dependencies are declared in one place (pyproject.toml)
• Standard Python packaging — familiar to contributors