Refactor SAR marker handling and add template management

- Updated CompassSarList and DetailedCompassDialog to use marker.displayName instead of marker.type.displayName.
- Enhanced DrawingLayer and DrawingMarkersLayer to support simple mode for drawing visibility and interaction.
- Added toggle switches in DrawingToolbar for showing/hiding received drawings and SAR markers.
- Modified MapMarkers to utilize custom emojis and display names for markers.
- Introduced RecipientSelectorSheet for selecting message recipients with search functionality.
- Refactored SarUpdateSheet to use SAR templates instead of marker types, allowing for emoji and name customization.
- Created SarTemplateEditDialog for adding and editing SAR templates with color selection and preview.

lib/utils/sar_message_parser.dart

@@ -81,6 +81,9 @@ class SarMessageParser {
       sarMarkerType: sarInfo.type,
       sarGpsCoordinates: sarInfo.location,
       sarNotes: sarInfo.notes, // Extract and store notes
+      sarCustomEmoji: sarInfo.type == SarMarkerType.unknown
+          ? sarInfo.emoji  // Preserve custom emoji for unknown types
+          : null,
     );
   }