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/src/dd-base-impl.d.ts

@@ -0,0 +1,69 @@
+/**
+ * dd-base-impl.ts 12.3.3
+ * Copyright (c) 2021-2025  Alain Dumesny - see GridStack root license
+ */
+/**
+ * Type for event callback functions used in drag & drop operations.
+ * Can return boolean to indicate if the event should continue propagation.
+ */
+export type EventCallback = (event: Event) => boolean | void;
+/**
+ * Abstract base class for all drag & drop implementations.
+ * Provides common functionality for event handling, enable/disable state,
+ * and lifecycle management used by draggable, droppable, and resizable implementations.
+ */
+export declare abstract class DDBaseImplement {
+    /**
+     * Returns the current disabled state.
+     * Note: Use enable()/disable() methods to change state as other operations need to happen.
+     */
+    get disabled(): boolean;
+    /**
+     * Register an event callback for the specified event.
+     *
+     * @param event - Event name to listen for
+     * @param callback - Function to call when event occurs
+     */
+    on(event: string, callback: EventCallback): void;
+    /**
+     * Unregister an event callback for the specified event.
+     *
+     * @param event - Event name to stop listening for
+     */
+    off(event: string): void;
+    /**
+     * Enable this drag & drop implementation.
+     * Subclasses should override to perform additional setup.
+     */
+    enable(): void;
+    /**
+     * Disable this drag & drop implementation.
+     * Subclasses should override to perform additional cleanup.
+     */
+    disable(): void;
+    /**
+     * Destroy this drag & drop implementation and clean up resources.
+     * Removes all event handlers and clears internal state.
+     */
+    destroy(): void;
+    /**
+     * Trigger a registered event callback if one exists and the implementation is enabled.
+     *
+     * @param eventName - Name of the event to trigger
+     * @param event - DOM event object to pass to the callback
+     * @returns Result from the callback function, if any
+     */
+    triggerEvent(eventName: string, event: Event): boolean | void;
+}
+/**
+ * Interface for HTML elements extended with drag & drop options.
+ * Used to associate DD configuration with DOM elements.
+ */
+export interface HTMLElementExtendOpt<T> {
+    /** The HTML element being extended */
+    el: HTMLElement;
+    /** The drag & drop options/configuration */
+    option: T;
+    /** Method to update the options and return the DD implementation */
+    updateOption(T: any): DDBaseImplement;
+}