Reverts the split-install approach. volkswagencarnet stays in
server/requirements.txt; the patch is applied in a single step
after pip install completes.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
client/install.sh → install_client.sh
server/install.sh → install_server.sh
Both scripts now resolve REPO_DIR as their own directory (repo root)
and use a shared .venv at the repo root instead of per-subdirectory
virtual environments.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>