fix(planner): give the day's optimize button room by dropping its label

Every button in the day's route-tools row hands the day somewhere: show the
route, open it in Google Maps, open it in CoMaps, reorder it. Two were
already icon-only. Optimize carried a label on flex: 1 with padding '6px 0',
which is no horizontal padding at all — survivable until CoMaps added a fifth
button, at which point the text sat hard against both edges of its own
button.

Icon-only now, matching the two beside it. The label stays as the accessible
name and the tooltip, so nothing about reaching the action changes, and the
row has room for whatever gets added to it next.

Closes #1981

client/src/components/Planner/DayPlanSidebar.tsx

@@ -2609,13 +2609,24 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                         >
                           <Compass size={14} strokeWidth={2} />
                         </button>
-                        <button onClick={() => handleOptimize(day.id)} className="bg-surface-hover text-content-secondary" style={{
-                          flex: 1, display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 5,
-                          padding: '6px 0', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 500, borderRadius: 8, border: 'none',
-                          cursor: 'pointer', fontFamily: 'inherit',
-                        }}>
-                          <RotateCcw size={12} strokeWidth={2} />
-                          {t('dayplan.optimize')}
+                        {/* Icon-only, like the two map hand-offs beside it (#1981). It
+                            was the one button here carrying a label with no room for
+                            it: `flex: 1` alongside `padding: '6px 0'` meant the text
+                            sat against both edges as soon as the row filled up, and
+                            the row gained a button when CoMaps arrived. The label
+                            stays as the accessible name and the tooltip. */}
+                        <button
+                          onClick={() => handleOptimize(day.id)}
+                          aria-label={t('dayplan.optimize')}
+                          title={t('dayplan.optimize')}
+                          className="bg-surface-hover text-content-secondary"
+                          style={{
+                            display: 'flex', alignItems: 'center', justifyContent: 'center',
+                            padding: '6px 10px', borderRadius: 8, border: 'none',
+                            cursor: 'pointer', fontFamily: 'inherit', flexShrink: 0,
+                          }}
+                        >
+                          <RotateCcw size={14} strokeWidth={2} />
                         </button>
                         <div style={{ display: 'flex', borderRadius: 8, overflow: 'hidden', border: '1px solid var(--border-faint)', flexShrink: 0 }}>
                           {routeProfileOptions.map(p => {