Function agents_md_guidance_block 

pub fn agents_md_guidance_block(sqz_path: &str) -> String

Build the markdown block that sqz appends to AGENTS.md.

The block is wrapped in HTML comment sentinels so remove_agents_md_guidance can locate and excise it byte-exact on uninstall. sqz_path is the absolute path of the sqz binary; we use it verbatim (no JSON escaping) because this is a markdown file the user reads — raw backslashes on Windows render correctly as-is, and the user can copy-paste the commands straight into their shell.