Fix autostage toggle and StringBuilder return bug

- Autostage field is _autostage on AscentSettings, not StagingController.
  The Autostage property setter manages Staging.Users.Add/Remove internally.
- Fix ShowMenu returning currentMenu.ToString() instead of
  stringBuilder.ToString()

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: vanillamc

MechJebRPM/MechJebProxy.cs

@@ -150,7 +150,7 @@ private static void InitializeFieldInfoCache()
             f_Ascent_LimitAoA = typeof(MechJebModuleAscentSettings).GetField(nameof(MechJebModuleAscentSettings.LimitAoA), BindingFlags.Public | BindingFlags.Instance);
             f_Ascent_CorrectiveSteering = typeof(MechJebModuleAscentSettings).GetField(nameof(MechJebModuleAscentSettings.CorrectiveSteering), BindingFlags.Public | BindingFlags.Instance);
             f_Ascent_AutoPath = typeof(MechJebModuleAscentSettings).GetField(nameof(MechJebModuleAscentSettings.AutoPath), BindingFlags.Public | BindingFlags.Instance);
-            f_Ascent_Autostage = typeof(MechJebModuleAscentSettings).GetField(nameof(MechJebModuleAscentSettings.Autostage), BindingFlags.Public | BindingFlags.Instance);
+            f_Ascent_Autostage = typeof(MechJebModuleAscentSettings).GetField(nameof(MechJebModuleAscentSettings._autostage), BindingFlags.Public | BindingFlags.Instance);
             f_Landing_DeployGears = typeof(MechJebModuleLandingAutopilot).GetField(nameof(MechJebModuleLandingAutopilot.DeployGears), BindingFlags.Public | BindingFlags.Instance);
             f_Landing_DeployChutes = typeof(MechJebModuleLandingAutopilot).GetField(nameof(MechJebModuleLandingAutopilot.DeployChutes), BindingFlags.Public | BindingFlags.Instance);
             f_Landing_UseRCS = typeof(MechJebModuleLandingAutopilot).GetField(nameof(MechJebModuleLandingAutopilot.RCSAdjustment), BindingFlags.Public | BindingFlags.Instance);
@@ -166,7 +166,8 @@ private static void InitializeFieldInfoCache()
             f_Thrust_DifferentialThrottle = typeof(MechJebModuleThrustController).GetField(nameof(MechJebModuleThrustController.DifferentialThrottle), BindingFlags.Public | BindingFlags.Instance);
             f_Thrust_TransKillH = typeof(MechJebModuleThrustController).GetField(nameof(MechJebModuleThrustController.TransKillH), BindingFlags.Public | BindingFlags.Instance);
 			f_Node_Autowarp = typeof(MechJebModuleNodeExecutor).GetField(nameof(MechJebModuleNodeExecutor.Autowarp), BindingFlags.Public | BindingFlags.Instance);
-			f_Staging_Autostage = typeof(MechJebModuleStagingController).GetField("autostage", BindingFlags.Public | BindingFlags.Instance);
+            // Staging autostage is actually AscentSettings._autostage — the property setter manages Staging.Users
+            f_Staging_Autostage = typeof(MechJebModuleAscentSettings).GetField(nameof(MechJebModuleAscentSettings._autostage), BindingFlags.Public | BindingFlags.Instance);
             f_Staging_DropSolids = typeof(MechJebModuleStagingController).GetField(nameof(MechJebModuleStagingController.DropSolids), BindingFlags.Public | BindingFlags.Instance);
             f_Docking_ForceRoll = typeof(MechJebModuleDockingAutopilot).GetField(nameof(MechJebModuleDockingAutopilot.forceRol), BindingFlags.Public | BindingFlags.Instance);
             f_Docking_OverrideSafeDistance = typeof(MechJebModuleDockingAutopilot).GetField(nameof(MechJebModuleDockingAutopilot.overrideSafeDistance), BindingFlags.Public | BindingFlags.Instance);

MechJebRPM/MechJebRPM.cs

@@ -618,7 +618,8 @@ private TextMenu BuildAscentStagingMenu()
             menu.selectedColor = JUtil.ColorToColorTag(Color.green);
             menu.disabledColor = JUtil.ColorToColorTag(Color.gray);
 
-            AddToggleItem(menu, "Autostage", mjCore.AscentSettings, MechJebProxy.f_Ascent_Autostage);
+            AddToggleItem(menu, "Autostage",
+                mjCore.AscentSettings, MechJebProxy.f_Staging_Autostage);
             AddNumericItem(menu, "Stop at Stage", mjCore.Staging.AutostageLimit,
                 1.0, v => v.ToString("F0"), null, true, 0, false, 0);
 
@@ -1672,7 +1673,7 @@ private TextMenu BuildUtilitiesMenu()
             menu.disabledColor = JUtil.ColorToColorTag(Color.gray);
 
             AddToggleItem(menu, "Autostage",
-                mjCore.Staging, MechJebProxy.f_Staging_Autostage);
+                mjCore.AscentSettings, MechJebProxy.f_Staging_Autostage);
             AddNumericItem(menu, "Stop at Stage", mjCore.Staging.AutostageLimit,
                 1.0, v => v.ToString("F0"), null, true, 0, false, 0);
             AddMenuItem(menu, "Stage Once", () => mjCore.Staging.AutostageOnce(null));
@@ -2440,7 +2441,7 @@ public string ShowMenu(int screenWidth, int screenHeight)
             stringBuilder.Clear();
             stringBuilder.AppendLine(pageTitle);
             currentMenu.ShowMenu(stringBuilder, screenWidth, screenHeight - 1);
-            return currentMenu.ToString();
+            return stringBuilder.ToString();
         }
         #endregion
     }