Update application_helper.rb

Fixed `point_speed` in `application_helper.rb` to properly convert velocity from m/s to km/h, round to 1 decimal, and safely handle nil or zero values.

Author: framesfree

app/helpers/application_helper.rb

@@ -169,9 +169,9 @@ def speed_text_color(speed)
   end
 
   def point_speed(speed)
-    return speed if speed.to_i <= 0
-
-    speed * 3.6
+    return "–" if speed.nil? || speed.to_f <= 0
+    speed = speed.to_f
+    "#{(speed * 3.6).round(1)}"
   end
 
   def days_left(active_until)