Function install_zed_mcp_config 

pub fn install_zed_mcp_config() -> Result<ZedMcpInstall>

Register sqz-mcp under context_servers.sqz in Zed’s settings.json.

• Missing file → created with just our entry.
• Strict-JSON file → surgically merged, all user keys preserved.
• Existing sqz entry → left alone (user customisation wins), ZedMcpInstall::AlreadyPresent.
• JSONC file → untouched, ZedMcpInstall::SkippedJsonc.