Implement legacy-style map markers with UI model mapping.

Replace default OSM pins with round value-based icons, add DTO-to-domain-to-UI marker mapping, and normalize no-value/offline styling while keeping ownership icon behavior stubbed for future auth integration.

Made-with: Cursor

sdk/src/main/graphql/MapLocations.graphql

@@ -1,5 +1,5 @@
-query MapMarkers($isOnline: Boolean!) {
-  locations(filter: { isOnline: $isOnline }) {
+query MapMarkers {
+  locations {
     _id
     name
     city
@@ -9,6 +9,7 @@ query MapMarkers($isOnline: Boolean!) {
     metricList
     currentValue {
       PMS25
+      Count
     }
   }
 }