fix(map): make the places filter sheet opaque

The sheet opens over the phone map, and with the default bar glass the map's
place names showed through the pool chips, the rating floors and the category
rows, which made them hard to read at 390px wide. It now uses the opaque sheet
material, like the other menus that open over busy content.

client/src/mobile/screens/trip/places/MPlacesFilterSheet.tsx

@@ -46,7 +46,9 @@ export default function MPlacesFilterSheet({ open, onClose, places, categories }
   const hasCategoryChoice = categories.length > 0 || places.some(p => p.category_id == null)
 
   return (
-    <MSheet open={open} onClose={onClose} variant="bottom" ariaLabel={t('places.filters')}>
+    // Opaque: the sheet opens over the map, and the default bar glass let the map's
+    // place names show through the chips and category rows (seen at 390px wide).
+    <MSheet open={open} onClose={onClose} variant="bottom" material="opaque" ariaLabel={t('places.filters')}>
       <div className="flex flex-none items-center border-b border-[color:var(--m-rowbr)] px-[18px] pb-[11px] pt-4">
         <div className="min-w-0 flex-1 text-[1.03125rem] font-bold text-m-ink">{t('places.filters')}</div>
         <MIconBtn variant="neutral" size={34} onClick={onClose} ariaLabel={t('common.close')}>