fix: resolve tool server disconnection on Windows 11

[Redrock453]

Description

Fixes tool server disconnection issue on Windows 11 caused by multiprocessing spawn behavior.

Problem

On Windows, multiprocessing uses 'spawn' method which re-imports modules in worker processes. This triggered:

• Argument parsing () at import time → crash
• RuntimeError check at import time → crash
• Signal handlers setup at import time → issues

Solution

• Moved argument parsing to block
• Created function for initialization
• now set at startup, not import time
• Workers can safely import the module without side effects

Testing

✅ Multiprocessing with spawn method (Windows behavior) ✅ Server startup with CLI arguments
✅ Health endpoint responding correctly ✅ Graceful rejection without sandbox mode

Changes

• strix/runtime/tool_server.py - main fix for multiprocessing
• strix/runtime/docker_runtime.py - command formatting cleanup
• .env.example - configuration reference for users

Tested on Linux with spawn context simulation (Windows behavior).

Closes #[issue-number if exists]