feat: add PyInstaller build for standalone binary distribution

[0xallam]

• Add PyInstaller spec file and build script for creating standalone executables
• Add install.sh for curl | sh installation from GitHub releases
• Add GitHub Actions workflow for multi-platform builds (macOS, Linux, Windows)
• Move sandbox-only deps (playwright, ipython, libtmux, etc.) to optional extras
• Make google-cloud-aiplatform optional ([vertex] extra) to reduce binary size
• Use lazy imports in tool actions to avoid loading sandbox deps at startup
• Add -v/--version flag to CLI