enable double-sided image plane and signal removal

frontend/apps/editor3d/app/src/pages/PageEnigma/Editor/scene.ts

@@ -206,6 +206,7 @@ class Scene {
           color: 0xffffff,
           map: texture,
           transparent: true,
+          side: THREE.DoubleSide,
         });
         obj = new THREE.Mesh(geometry, image_material);
         obj.userData["media_id"] = name;

frontend/libs/components/gallery-modal/src/lib/galleryDnd.ts

@@ -3,7 +3,6 @@ import {
   galleryModalVisibleDuringDrag,
   galleryReopenAfterDragSignal,
 } from "./galleryModalSignals";
-import { signal } from "@preact/signals-react";
 
 interface DragState {
   item: GalleryItem | null;
@@ -25,14 +24,6 @@ const dragState: DragState = {
 
 const dragThreshold = 5;
 
-export const onImageDropSignal = signal<
-  ((item: GalleryItem, position: { x: number; y: number }) => void) | null
->(null);
-
-export function setOnImageDrop(cb: typeof onImageDropSignal.value) {
-  onImageDropSignal.value = cb;
-}
-
 function onPointerDown(event: React.PointerEvent, item: GalleryItem) {
   if (event.button !== 0) return;
   dragState.item = item;