Removes manual pip installation of black, flake8, and isort that was causing
build failures due to permission errors and PEP 668 restrictions. These tools
are already provided by the installed VS Code Python extensions and don't need
to be manually installed via pip.
This reverts to the original working devcontainer approach where development
tools are handled through VS Code extensions rather than manual package
installations, avoiding both permission issues and tool duplication.
Fixes devcontainer build failure and maintains the intended development
environment functionality.
707e03a9a8