N°8641 - Dashboard editor front-end first commit for Form SDK integration.

* No dashlet edition
* Dashboard are not persisted
* Unable to load a dashboard from an endpoint (refresh)
* Grid library need proper npm integration

node_modules/gridstack/dist/dd-droppable.d.ts

@@ -0,0 +1,26 @@
+/**
+ * dd-droppable.ts 12.3.2
+ * Copyright (c) 2021-2025  Alain Dumesny - see GridStack root license
+ */
+import { DDBaseImplement, HTMLElementExtendOpt } from './dd-base-impl';
+import { DDUIData } from './types';
+export interface DDDroppableOpt {
+    accept?: string | ((el: HTMLElement) => boolean);
+    drop?: (event: DragEvent, ui: DDUIData) => void;
+    over?: (event: DragEvent, ui: DDUIData) => void;
+    out?: (event: DragEvent, ui: DDUIData) => void;
+}
+export declare class DDDroppable extends DDBaseImplement implements HTMLElementExtendOpt<DDDroppableOpt> {
+    el: HTMLElement;
+    option: DDDroppableOpt;
+    accept: (el: HTMLElement) => boolean;
+    constructor(el: HTMLElement, option?: DDDroppableOpt);
+    on(event: 'drop' | 'dropover' | 'dropout', callback: (event: DragEvent) => void): void;
+    off(event: 'drop' | 'dropover' | 'dropout'): void;
+    enable(): void;
+    disable(forDestroy?: boolean): void;
+    destroy(): void;
+    updateOption(opts: DDDroppableOpt): DDDroppable;
+    /** item is being dropped on us - called by the drag mouseup handler - this calls the client drop event */
+    drop(e: MouseEvent): void;
+}