also bind Cmd+Y to redo on macOS

- check_scene_for_updates was resetting undoIndex to 0 on every mouseUp,
  even when the scene was unchanged; redo became a silent no-op after
  any innocuous click. Only reset when a command is actually pushed.
- undo past the bottom of the stack re-undid the oldest command forever
  due to the clamp-then-index pattern; early-return instead.
- Pushing a new command after undo left stale redo-future entries on
  the stack; added dropRedoHistory() called before each push so new
  work replaces the branch the user had undone past.

frontend/apps/artcraft/app/src/pages/PageEnigma/Editor/keybinds_controls.ts

@@ -375,25 +375,53 @@ export class MouseControls {
 
     if ((event.ctrlKey || event.metaKey) && !this.isProcessing) {
       const keyLower = event.key.toLowerCase();
-      if (keyLower === "z") {
-        // redo
+      if (keyLower === "z" && !event.shiftKey) {
+        // undo
+        event.preventDefault();
         this.isProcessing = true;
-        await this.sceneManager?.redo();
-        this.isProcessing = false;
+        try {
+          await this.sceneManager?.undo();
+        } finally {
+          this.isProcessing = false;
+        }
+      } else if (keyLower === "z" && event.shiftKey) {
+        // redo (Ctrl+Shift+Z / Cmd+Shift+Z)
+        event.preventDefault();
+        this.isProcessing = true;
+        try {
+          await this.sceneManager?.redo();
+        } finally {
+          this.isProcessing = false;
+        }
+      } else if (keyLower === "y") {
+        // redo (Ctrl+Y on Windows/Linux, Cmd+Y on macOS)
+        event.preventDefault();
+        this.isProcessing = true;
+        try {
+          await this.sceneManager?.redo();
+        } finally {
+          this.isProcessing = false;
+        }
       } else if (keyLower === "c") {
         // Copy
         event.preventDefault();
         event.stopPropagation();
         this.isProcessing = true;
-        await this.sceneManager?.copy();
-        this.isProcessing = false;
+        try {
+          await this.sceneManager?.copy();
+        } finally {
+          this.isProcessing = false;
+        }
       } else if (keyLower === "v") {
         // Paste
         event.preventDefault();
         event.stopPropagation();
         this.isProcessing = true;
-        await this.sceneManager?.paste();
-        this.isProcessing = false;
+        try {
+          await this.sceneManager?.paste();
+        } finally {
+          this.isProcessing = false;
+        }
       } else if (event.key === "0") {
         // Stats Menu
         this.enable_stats();

frontend/apps/artcraft/app/src/pages/PageEnigma/Editor/scene_manager_api.ts

@@ -118,10 +118,10 @@ export class SceneManager implements SceneManagerAPI {
   }
 
   public async undo() {
-    this.undoIndex += 1;
     if (this.undoIndex >= this.undoStack.length) {
-      this.undoIndex = this.undoStack.length;
+      return;
     }
+    this.undoIndex += 1;
     const undoCommand = this.undoStack.at(
       this.undoStack.length - this.undoIndex,
     );
@@ -131,18 +131,30 @@ export class SceneManager implements SceneManagerAPI {
   }
 
   public async redo() {
+    if (this.undoIndex <= 0) {
+      return;
+    }
     const undoCommand = this.undoStack.at(
       this.undoStack.length - this.undoIndex,
     );
     await undoCommand?.redo();
     this.undoIndex -= 1;
-    if (this.undoIndex <= -1) {
-      this.undoIndex = 0;
-    }
     this.updateOutliner(); // In the future we will address this because of its relational issues with editor and the current class.
     this.lastSceneState = this.getSceneState();
   }
 
+  // Drop any redo-future before pushing a fresh command so the new action
+  // replaces the branch of history the user had undone past.
+  private dropRedoHistory() {
+    if (this.undoIndex > 0) {
+      this.undoStack = this.undoStack.slice(
+        0,
+        this.undoStack.length - this.undoIndex,
+      );
+      this.undoIndex = 0;
+    }
+  }
+
   public async create(
     media_token: string,
     name: string,
@@ -467,6 +479,7 @@ export class SceneManager implements SceneManagerAPI {
   }
 
   public async add_creation_undostack(object: THREE.Object3D) {
+    this.dropRedoHistory();
     this.undoStack.push(
       new CreationSceneItem(this, {
         object_uuid: object.uuid,
@@ -488,6 +501,7 @@ export class SceneManager implements SceneManagerAPI {
       const is_transform = this.is_transformation(sceneState);
       const is_userdata = this.is_userdata(sceneState);
 
+      this.dropRedoHistory();
       this.undoStack = this.undoStack.slice(-16);
 
       if (is_deleted != "") {
@@ -558,7 +572,6 @@ export class SceneManager implements SceneManagerAPI {
         }
       }
     }
-    this.undoIndex = 0;
     this.lastSceneState = sceneState;
   }
 }

frontend/apps/artcraft/app/src/pages/PageEnigma/signals/hotkeys.ts

@@ -23,7 +23,7 @@ export const isHotkeyDisabled = ()=>{
 export const disableHotkeyInput = (level: number)=>{
   if(hotkeysStatus.value.disabled === true){
     if (level > hotkeysStatus.value.disabledBy){
-      hotkeysStatus.value.disabledBy === level;
+      hotkeysStatus.value = { ...hotkeysStatus.value, disabledBy: level };
     }
   }else{
     hotkeysStatus.value = {