Add MapReport decoding and formatting support

- Added DecodeMapReport function to decode protobuf MapReport messages
- Added FormatMapReport function to display MapReport data in human-readable format
- Updated FormatTopicAndMapData to use the proper decoder and formatter
- Improved error handling with fallback to raw display

🤖 Generated with [Claude Code](https://claude.ai/code)

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

decoder/decoder.go

@@ -288,6 +288,15 @@ func DecodeJSONMessage(payload []byte) (map[string]interface{}, error) {
 	return jsonData, nil
 }
 
+// DecodeMapReport decodes a MapReport protobuf message (format "map")
+func DecodeMapReport(payload []byte) (*pb.MapReport, error) {
+	var mapReport pb.MapReport
+	if err := proto.Unmarshal(payload, &mapReport); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal MapReport: %v", err)
+	}
+	return &mapReport, nil
+}
+
 // IsASCII checks if the given byte array contains only ASCII characters
 func IsASCII(data []byte) bool {
 	for _, b := range data {