Motivation

• Replace the old PYWRAP_NO_INSTALL flag with PYWRAP_INSTALL_DEPS to make the intent explicit (enable installs vs disable installs).
• Make dependency installation opt-in by default so dependencies are only installed when PYWRAP_INSTALL_DEPS=1.
• Ensure the CLI behavior and logging reflect the new flag semantics.
• Update documentation to describe the new environment variable and its default.

Description

• In python3 replaced no_install = _bool_env("PYWRAP_NO_INSTALL", False) with install_deps = _bool_env("PYWRAP_INSTALL_DEPS", False).
• Inverted the install/skipping logic so dependencies are installed only when install_deps is true and otherwise a log message indicates skipping.
• Updated README.md to document PYWRAP_INSTALL_DEPS and state the default is 0.
• Changes touch python3 and README.md.

Testing

• No automated tests were run on this change.

Codex Task