Accept .exe binary name on Linux/macOS and fix AlwaysOn battery threshold

build-macos.sh ships the macOS binary as eu07.exe, so IsValidBinaryFile
must accept that extension on non-Windows too. Also fix the AlwaysOn
battery default check to use a proper near-zero epsilon instead of an
overly broad <0.2 threshold that clobbered legitimate low velocities.

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

StarterNG/Classes/Settings.cs

@@ -256,8 +256,10 @@ public sealed class Settings
             return false;
         if (OperatingSystem.IsWindows())
             return ext == ".exe";
-        // Linux / macOS: no extension (eu07) or a known binary suffix
-        return ext.Length == 0 || ext is ".x86_64" or ".run" or ".appimage";
+        // Linux / macOS: no extension (eu07), a known binary suffix, or .exe
+        // (some builds - notably this project's own build-macos.sh - ship the
+        // macOS binary under the historical "eu07.exe" name).
+        return ext.Length == 0 || ext is ".exe" or ".x86_64" or ".run" or ".appimage";
     }
 
     private static readonly Encoding FileEncoding = ResolveEncoding();

StarterNG/MainWindow.axaml.cs

@@ -105,7 +105,7 @@ public partial class MainWindow : Window
             trainset.Velocity = Settings.Instance.BatteryDefault switch
             {
                 BatteryDefault.AlwaysOff => 0f,
-                BatteryDefault.AlwaysOn  => trainset.OriginalVelocity < 0.2f ? 0.1f : trainset.OriginalVelocity,
+                BatteryDefault.AlwaysOn  => MathF.Abs(trainset.OriginalVelocity) < 0.01f ? 0.1f : trainset.OriginalVelocity,
                 _                        => trainset.OriginalVelocity
             };
         }