Add settings page for managing forecasting API key and URL via UI

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/node_modules/es-toolkit/dist/array/flatMapDeep.d.ts

@@ -0,0 +1,19 @@
+import { ExtractNestedArrayType } from "./flattenDeep.js";
+
+//#region src/array/flatMapDeep.d.ts
+/**
+ * Recursively maps each element in an array using a provided iteratee function and then deeply flattens the resulting array.
+ *
+ * @template T - The type of elements within the array.
+ * @template U - The type of elements within the returned array from the iteratee function.
+ * @param arr - The array to flatten.
+ * @param iteratee - The function that produces the new array elements. It receives the element, its index, and the array.
+ * @returns A new array that has been flattened.
+ *
+ * @example
+ * const result = flatMapDeep([1, 2, 3], n => [[n, n]]);
+ * // [1, 1, 2, 2, 3, 3]
+ */
+declare function flatMapDeep<T, U>(arr: readonly T[], iteratee: (item: T, index: number, array: readonly T[]) => U): Array<ExtractNestedArrayType<U>>;
+//#endregion
+export { flatMapDeep };