feat: add PyInstaller build for standalone binary distribution

- 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
- Add website and Discord links to completion message
- Binary size: ~97MB (down from ~120MB with all deps)

strix/tools/python/python_actions.py

@@ -2,8 +2,6 @@ from typing import Any, Literal
 
 from strix.tools.registry import register_tool
 
-from .python_manager import get_python_session_manager
-
 
 PythonAction = Literal["new_session", "execute", "close", "list_sessions"]
 
@@ -15,6 +13,8 @@ def python_action(
     timeout: int = 30,
     session_id: str | None = None,
 ) -> dict[str, Any]:
+    from .python_manager import get_python_session_manager
+
     def _validate_code(action_name: str, code: str | None) -> None:
         if not code:
             raise ValueError(f"code parameter is required for {action_name} action")