Re-verify subagent listing claims against the source post

A subagent's final report combined the title of one post with the price and building of a sibling post from the same author, and the main agent passed it to the user as fact. When parallel agents harvest listings or records, re-fetch the primary source before presenting any item, especially where the agent 'cross-references' posts. Check that address, price and terms all come from the same post id. Also treat unexplained building shorthand as unknown: a post saying only "7 minutes from" campus and a bare "1905" turned out to be a bus-only complex, not the walkable building it had been guessed to be.