tiltReturn

How much of the tilt is still applied, millisSinceRelease after the finger left.

The press is instant and the return is not: the plane holds where it was for Tilt.RETURN_DELAY_MILLIS, then unwinds linearly over Tilt.RETURN_DURATION_MILLIS. The pause is the part that matters — it is what makes a tap feel acknowledged rather than merely registered, and it is why a naive spring-back reads as twitchy.

A pure function because a still frame cannot show a return, and something has to be checkable.