Plotly has no gantt trace: a schedule is drawn as horizontal bars whose
base array floats each one onto a date axis, which is what
plotly.express.timeline emits. MAIDR reads that back as
intervals rather than as bars — an interval has two positions and no
baseline, so its length is a difference a reader has to be told. The
pitch carries the length and the stereo position carries the start,
mapped along the whole axis, so two tasks that line up sound like they
line up and a lane whose work happens late sounds late.