pub fn install_zed_guidance(project_dir: &Path, sqz_path: &str) -> Result<bool>Expand description
Install sqz’s Zed guidance block into the project’s effective Zed
instruction file (.rules when present, else AGENTS.md).
Idempotent: returns Ok(false) when the target already contains the
block. Appends to existing files rather than clobbering them.