The running status glyph clipped its cosine throb to a blank column below
STATUS_FADE_MIN_OPACITY, so each breath read as bold->dim->disappear rather
than bold->dim->bold. Remove the cutoff and the constant; the trough now
renders as the dimmest gray, giving a symmetric breathe. Turn-boundary
appear/disappear is unchanged (fade envelope and non-truecolor visible
threshold).