fix(dawarich): the places rail scrolls again with the panel open

The panel sat in a wrapper that could not shrink and did not scroll, so opening it took
whatever height the day's stays needed — forty of them is over 3000px — and squeezed the
places list, which is the flex child that scrolls, down to nothing. The rail stopped
scrolling and most of the stays sat below the bottom edge with no way to reach them.

The wrapper is capped at half the rail and scrolls on its own. Open, the stays are all
reachable and the list underneath is still a list; shut, nothing changes, because the cap
only bites once the content passes it.

client/src/components/Planner/PlacesSidebar.tsx

@@ -70,7 +70,13 @@ const PlacesSidebar = React.memo(function PlacesSidebar(props: PlacesSidebarProp
           nothing at all when there is nothing pending — an integration that is
           connected and quiet should be invisible rather than a permanent empty
           card. */}
-      <div style={{ padding: '0 12px 8px', flexShrink: 0 }}>
+      {/* Capped and scrolling on its own. Open, the panel is as tall as the day has stays —
+          ten of them on a day of driving — and with nothing holding it back it pushed the
+          places list, which is the flex child that scrolls, down to nothing: the rail
+          stopped scrolling and half the stays sat below the bottom edge with no way to
+          reach them. Half the rail at most, so the list it sits above is always still a
+          list. */}
+      <div style={{ padding: '0 12px 8px', flexShrink: 0, minHeight: 0, maxHeight: '50%', overflowY: 'auto' }}>
         <DawarichSuggestionsPanel
           tripId={tripId}
           trips={[{ id: tripId, label: t('dawarich.accept.thisTrip') }]}