fix Vue nodes capturing wheel event when Ctrl+Shift+drag zooming (#5791)

## Summary

Fixed canvas read-only state during Ctrl+Shift drag-to-zoom to prevent
node interaction conflicts. This fix also benefits Litegraph nodes.

## Changes

- **What**: Canvas becomes read-only during [Ctrl+Shift drag
zoom](https://developer.mozilla.org/en-US/docs/Web/API/PointerEvent)
operations and restores original state when finished
- **What**: Added browser test coverage for zoom interaction behavior

## Review Focus

State restoration on zoom interruption and edge cases where drag zoom is
cancelled mid-operation.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5791-fix-Vue-nodes-capturing-wheel-event-when-Ctrl-Shift-drag-zooming-27a6d73d3650817d888ee59f8f7fcb01)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/lib/litegraph/src/LGraphCanvas.ts

@@ -688,8 +688,8 @@ export class LGraphCanvas
 
   /** If true, enable drag zoom. Ctrl+Shift+Drag Up/Down: zoom canvas. */
   dragZoomEnabled: boolean = false
-  /** The start position of the drag zoom. */
-  #dragZoomStart: { pos: Point; scale: number } | null = null
+  /** The start position of the drag zoom and original read-only state. */
+  #dragZoomStart: { pos: Point; scale: number; readOnly: boolean } | null = null
 
   getMenuOptions?(): IContextMenuValue<string>[]
   getExtraMenuOptions?(
@@ -2188,7 +2188,12 @@ export class LGraphCanvas
       !e.altKey &&
       e.buttons
     ) {
-      this.#dragZoomStart = { pos: [e.x, e.y], scale: this.ds.scale }
+      this.#dragZoomStart = {
+        pos: [e.x, e.y],
+        scale: this.ds.scale,
+        readOnly: this.read_only
+      }
+      this.read_only = true
       return
     }
 
@@ -3125,7 +3130,7 @@ export class LGraphCanvas
   #processDragZoom(e: PointerEvent): void {
     // stop canvas zoom action
     if (!e.buttons) {
-      this.#dragZoomStart = null
+      this.#finishDragZoom()
       return
     }
 
@@ -3143,6 +3148,13 @@ export class LGraphCanvas
     this.graph.change()
   }
 
+  #finishDragZoom(): void {
+    const start = this.#dragZoomStart
+    if (!start) return
+    this.#dragZoomStart = null
+    this.read_only = start.readOnly
+  }
+
   /**
    * Called when a mouse move event has to be processed
    */
@@ -3524,6 +3536,8 @@ export class LGraphCanvas
     const { graph, pointer } = this
     if (!graph) return
 
+    this.#finishDragZoom()
+
     LGraphCanvas.active_canvas = this
 
     this.adjustMouseEvent(e)