Legend progress bar draws no empty segments, so its left end is rounded again

A zero-width segment button was still rendered: an invisible tab stop, and the
first child that took the bar's rounded left end. Segments with no width are
now left out.

library/components/legends/LegendProgressBar.vue

@@ -190,8 +190,10 @@ function hide() { activeKey.value = null }
            segments are drawn left→right, so for prayer the full-coverage colour
            fills the span from the left and the has-prayer colour completes it. -->
       <span class="lpb-span" :style="{ width: coveredPct + '%' }" :data-span-pct="coveredPct.toFixed(2)">
+        <!-- An empty segment is not drawn: a zero-width button is an invisible tab stop, and it took the
+             bar's rounded left end (rega). -->
         <button
-          v-for="seg in spanSegs" :key="seg.key"
+          v-for="seg in spanSegs.filter(s => segPctOfSpan(s) > 0)" :key="seg.key"
           type="button"
           class="lpb-seg"
           :class="{ active: activeKey === seg.key }"