Status bar — error
StatusKind::Error. Pill goes red, dot stops pulsing (the user shouldn't
mistake an error for in-progress work). FPS reads 0 because the
renderer is no longer ticking; encoder cell shows the codec without a
live bitrate; size cell freezes at the last known value. Detail text
carries the actual error — VideoToolbox: out of memory here.
Whatever appears in detail is the only specific information the user
gets at this layer; a longer error log lives in the encoder card (a
future chunk). The status bar is a glanceable summary, not a debug pane.