The web UI was showing a raw ~500k-character stdout/stderr dump on a failed build — go-pmtiles' extract logs one progress line per chunk, which is fine on a terminal (it overwrites itself) but not captured non-interactively. command_output now keeps just the tail, and the status line renders it with preserved line breaks in a scrollable box instead of one unreadable blob. Root cause of the actual failure (terrain build dying ~11 minutes in with an HTTP/2 stream reset): go-pmtiles' default --overfetch=0.05 merged this multi-country planet.pmtiles extract into a single ~60GB request with no way to resume after a dropped stream. --overfetch=0 splits it into many smaller requests instead.