A lap can span many minutes, so plotting one flat value per lap hid real
within-lap variation -- a single-lap hill repeat rendered as a dead-flat
line despite the pace/HR swinging throughout it. The actual pace/HR trace
now comes from activity_samples (per-second telemetry) when available,
looking up each sample's enclosing lap only for the target band/phase
color. Falls back to the previous lap-stepped rendering when an activity
has no samples.
Christophe Vila
7f0373f2f3