The title field of document.inspect and the document.open reply is the
document's tab name, which comes from the file name once the document
is saved to or opened from a file. A client had to call file.info or
document.info to read the File Info title, so reading a saved
document's title from these replies gave the file name instead.
Both replies now add fileInfoTitle, the title file.info reports, and
keep title as it was. docs/mcp.md's File Info section describes both.