🔒 Fix command injection vulnerability in stdlib process.spawn

[Tcode-Motion]

🎯 What: Fixed a critical command injection vulnerability in the std.process.spawn function within the techscript_stdlib crate.
⚠️Risk: The process.spawn function was executing user-provided command strings by passing them directly to the Windows shell (cmd /C <command>). This allowed attackers to execute arbitrary, unconstrained OS commands via shell meta-characters (like &, |, ;), completely bypassing language-level security boundaries.
🛡️ Solution: Modified process.spawn to securely parse the user-provided command string into its component program and arguments using the shlex crate. These arguments are now passed directly to std::process::Command::new(), completely circumventing the shell and neutralizing injection vectors. Added a comprehensive test suite to verify correct parsing and security behavior.

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PR created automatically by Jules for task 6640346681076279577 started by @Tcode-Motion

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