Panel readout shows the wire values while the dot stays physical

With Invert Y checked the readout claimed "Y 80" while the AnalogReply
carried -80. The flip is factored into VRioDevice.WireY, shared by the
reply builder and the new GetWireAxis accessor; the canvas readout uses
a WireAxisProvider fed from it, and toggling the checkbox repaints so
the sign flips in place. Dot and gauges keep tracking the stick.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/VRio.Core.Tests/VRioDeviceTests.cs

@@ -77,7 +77,8 @@ public class VRioDeviceTests
 
         byte[] p = Assert.Single(wire.Packets).Payload;
         Assert.Equal(-3000, AnalogCodec.Combine(p[6], p[7]));
-        Assert.Equal(3000, device.GetAxis(RioAxis.JoystickY)); // the panel's view is unflipped
+        Assert.Equal(3000, device.GetAxis(RioAxis.JoystickY));      // the panel's dot is unflipped
+        Assert.Equal(-3000, device.GetWireAxis(RioAxis.JoystickY)); // the panel's readout matches the wire
 
         // Full negative deflection: -Min is one past Max, so it clamps rather than throws.
         device.SetAxis(RioAxis.JoystickY, AnalogCodec.Min);