Phone photos store heading (EXIF GPSImgDirection) as a rational over 0.00-359.99
— two decimal places. Match that: heading step 1 -> 0.01 on the FLOAT inputs, and
the compass field steps/rounds to 0.01 too. The rendered value was always the raw
float (a driven fractional heading already rendered correctly); this only stops
the on-node number from displaying a misleading whole-degree value.