Manual STI angles flip the vector directions upstream if the flow is bottom to top and initial flow angle guess is 0°

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Bug Report

Current Behavior A clear and concise description of the behavior.

If the initial flow direction is 0° for a flow in that direction (flow going from bottom to top of the image), then manual STI angle corrections will "flip" and show up as flowing in the upstream direction of the STIV vectors. The STI manual velocities will have the correct sign, but when applied, the Discharge Tab will now report negative unit qs for all auto stations, and positive qs for the manual stations. This condition is verified for 0°, but may also apply for 360°. I did not test other cardinal directions.

Expected behavior/code A clear and concise description of what you expected to happen (or code).

The manual STI angles should not flip all of the other flow angles and should plot correctly in the STIV tab.

Possible Solution

A workaround for now is to set the initial flow direction to 1°. This completely fixes the math, and everything works as it should. I suspect that means that the angle conversion functions are not correctly handling the 0° case.

Additional context/Screenshots Add any other context about the problem here. If applicable, add screenshots to help explain.

Noticed in v0.99.0.1