[@mantine/spotlight] Fix spotlight not working correctly with shadow …

…DOM (#6400)

* Search for the action item in the document or in ShadowDOMs.

* ESLint: Unary operator '++' used.(no-plusplus)

* Extend type instead of casting it

* Use `document` as default root, so we can omit it from the two method calls.

* Fix order of arguments

* Check if `state.listId` is truthy.

packages/@mantine/spotlight/src/spotlight.store.ts

@@ -52,9 +52,37 @@ export function setListId(id: string, store: SpotlightStore) {
   store.updateState((state) => ({ ...state, listId: id }));
 }
 
+function findElementByQuerySelector<T extends HTMLElement>(
+  selector: string,
+  root: Document | Element | ShadowRoot = document
+): T | null {
+  // Directly try to find the element in the current root.
+  const element = root.querySelector<T>(selector);
+  if (element) return element;
+
+  // Iterate through all children of the current root.
+  const children = root instanceof ShadowRoot ? root.host.children : root.children;
+  for (let i = 0; i < children.length; i += 1) {
+    const child = children[i];
+
+    // Recursively search in the child's shadow root if it exists.
+    if (child.shadowRoot) {
+      const shadowElement = findElementByQuerySelector<T>(selector, child.shadowRoot);
+      if (shadowElement) return shadowElement;
+    }
+
+    // Also, search recursively in the child itself if it does not have a shadow root or the element wasn't found in its shadow root.
+    const nestedElement = findElementByQuerySelector<T>(selector, child);
+    if (nestedElement) return nestedElement;
+  }
+
+  // Return null if the element isn't found in the current root or any of its shadow DOMs.
+  return null;
+}
+
 export function selectAction(index: number, store: SpotlightStore): number {
   const state = store.getState();
-  const actionsList = document.getElementById(state.listId);
+  const actionsList = state.listId ? findElementByQuerySelector(`#${state.listId}`) : null;
   const selected = actionsList?.querySelector<HTMLButtonElement>('[data-selected]');
   const actions = actionsList?.querySelectorAll<HTMLButtonElement>('[data-action]') ?? [];
   const nextIndex = index === -1 ? actions.length - 1 : index === actions.length ? 0 : index;
@@ -78,7 +106,9 @@ export function selectPreviousAction(store: SpotlightStore) {
 
 export function triggerSelectedAction(store: SpotlightStore) {
   const state = store.getState();
-  const selected = document.querySelector<HTMLButtonElement>(`#${state.listId} [data-selected]`);
+  const selected = findElementByQuerySelector<HTMLButtonElement>(
+    `#${state.listId} [data-selected]`
+  );
   selected?.click();
 }