frontend: RTL sidebar arrow placement + reverse-geocode clinic location

- Arabic RTL: stack the collapse arrow/bell above the nav icons instead of
  pinning them to the opposite edge; mirror the panel-toggle glyph; flip the
  notifications popover to open toward the content side.
- "Use my current location" now reverse-geocodes (OpenStreetMap Nominatim) to
  fill address/city/country, not just latitude/longitude, with a graceful
  coordinates-only fallback. New settings.location.geoPartial key in all 5 locales.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/components/ui/sidebar.tsx

@@ -299,7 +299,8 @@ export function SidebarTrigger({
       variant="ghost"
       {...props}
     >
-      <PanelLeftIcon />
+      {/* Mirror the panel arrow under RTL so it points toward the sidebar edge. */}
+      <PanelLeftIcon className="rtl:rotate-180" />
       <span className="sr-only">Toggle Sidebar</span>
     </Button>
   );