Problem

The current dev.sh script installs Python packages globally using pip3 install -r requirements.txt when running the integration testsuite. This pollutes the global Python environment, which can:

• Conflict with system packages
• Interfere with other Python projects
• Not follow Python best practices for dependency isolation

Proposed Solution

Add functionality to the dev.sh script to:

1. Create a Python virtual environment in the testsuite/ directory (e.g., testsuite/venv)
2. Install packages within that virtual environment instead of globally
3. Use the virtual environment to run the testsuite
4. Provide an option to control this behavior (e.g., --use-venv flag)

Additional Context

• Related to PR: fix: enhance terminal pixel detection and response handling #904
• Raised in comment: fix: enhance terminal pixel detection and response handling #904 (comment)
• Requested by: @lazysegtree

This would improve the development experience and follow Python best practices for dependency management.