defensive shell script configuration

Configure shell scripts with defensive practices to ensure reliability and debuggability. Use appropriate set options for error handling and debugging, implement safe defaults that require explicit opt-in for risky operations, and preserve execution state when changing directories.

Key practices:

• Use set -ex instead of just set -e to output commands as they execute for better debugging
• Default to safe behaviors and require explicit conditions for potentially risky operations (e.g., defaulting to dev releases and opting into stable releases only on exact matches)
• Preserve directory state using pushd/popd instead of cd when temporary directory changes are needed
• Document supported configuration values and their behaviors clearly

Example of defensive directory handling:

# Instead of:
cd "${PROJECT_PATH}"
pipenv install

# Use:
pushd "${PROJECT_PATH}"
pipenv install
popd

This approach prevents unintended side effects on subsequent script execution and makes scripts more predictable in different environments.