Invert Y on the wire, not in the router: the panel keeps tracking the stick

InputRouter.InvertJoystickY flipped the stored axis, so the X/Y dot and
readout moved opposite the physical stick. The toggle now lives on
VRioDevice and negates joystick Y only while building AnalogReply: local
state keeps the physical direction for every source (pad, keys, panel
drags) and only the host sees the flip. Negating a full -8192 deflection
lands one past the 14-bit Max, so the reply clamps it to 8191.

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

src/VRio.Core/Input/InputRouter.cs

@@ -57,13 +57,6 @@ public sealed class InputRouter
     /// <summary>A routed address went down (true) or came back up (false) — for panel highlighting.</summary>
     public event Action<int, bool>? AddressHeldChanged;
 
-    /// <summary>
-    /// Flip the sign of the composed joystick Y before it reaches the device.
-    /// Applies to all routed sources (keys and pad) alike; panel drags write
-    /// the device directly and are unaffected.
-    /// </summary>
-    public bool InvertJoystickY { get; set; }
-
     /// <summary>
     /// The active bindings. Assigning releases everything currently held
     /// (keys, toggles, pad buttons) so a reload never strands a pressed input.
@@ -223,8 +216,6 @@ public sealed class InputRouter
                 if (b.Rate <= 0f)
                     total += Shape(_pad.Axis(b.Source), b);
             }
-            if (InvertJoystickY && axis == RioAxis.JoystickY)
-                total = -total;
             total = ClampNorm(axis, total);
 
             short raw = (short)Math.Round(total * RioAxisRange.Full(axis));