Function is_architect_command_allowed 

pub fn is_architect_command_allowed(command_line: &str) -> bool

Fail-closed read-only policy for architect shell commands.

The normal allowlist checks every nested command, but a few nominally read-only programs have options that execute helpers or write files. Validate those options here as well so rg --pre, git diff --ext-diff, and git show --output=... cannot turn the architect shell into a mutation path.