OK, some points that might make a difference.
Since you are originaly using a .C file (originally only .CPP was supported, so it might be safer to have all files as .CPP/.H) you might want to add the #pragma SPARK_NO_PREPROCESSOR in your .INO file to have the proprocessor treat it like a standard C file.
And Particle Dev does also accept one .INO file as main project file, so for consistence use that extention and the #pragma for both IDEs.
Next, the Web IDE is known to have problems with #include <...>, so try to convert this into #include "...", which should work for all IDEs.
I’ve added a break between the main snippet and the header - I hope I’ve set it right there.