plot_slices_3d builds its own deflection filename tag, so it finds no

[1-Bort-1]

plot_slices_3d builds its own deflection filename tag, so it finds no .dat for a negative or fractional delta

generated_slices in ext/VortexStepMethodMakieExt.jl:1614-1615 rolls its own tag for the per-deflection file instead of calling AirfoilAero.delta_suffix (src/section_aero.jl:105-118), which is the function that named the file when generate_airfoils wrote it:

    deg = round(float(delta); digits=1)
    tag = "_d" * (deg == round(deg) ? string(Int(deg)) : string(deg)) * ".dat"

delta_suffix substitutes m for the minus sign and p for the decimal point; this does not. The two agree only on positive integer degrees:

delta	written	plot_slices_3d looks for
10	_d10.dat	_d10.dat
-3	_dm3.dat	_d-3.dat
2.5	_d2p5.dat	_d2.5.dat
-40	_dm40.dat	_d-40.dat

So plot_slices_3d(path; delta=-10) draws no deflected contour at all and warns No generated .dat for delta=-10°; generated deflections are named airfoils/<i>_d<degrees>.dat — a message that also states the wrong scheme. On the SK100's delta_range = -40:10:40 that is four of the eight non-zero deflections, silently blind. #294's follow-up work generates both signs, so this starts firing.

The fix is to delete the local tag and call AirfoilAero.delta_suffix(deg2rad(delta)) — generated_slices takes delta in degrees, delta_suffix in radians — leaving one source for the name, and to correct the warning text to what that function produces. A test that writes a negative-delta .dat and reads it back through generated_slices fails before the change.

Found while working out figures for #294 (#297); out of scope there.

[1-Bort-1]

Deleting generated_slices' hand-rolled _d tag in ext/VortexStepMethodMakieExt.jl and calling AirfoilAero.delta_suffix(deg2rad(delta)) instead, so negative and fractional deflections find their .dat; correcting the warning text to the scheme that function produces. Regression test writes a negative-delta .dat and reads it back. Nothing stacked — no open PR touches the extension. Leaving the rest of plot_slices_3d alone.