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/compat/array/nth.d.ts

@@ -0,0 +1,15 @@
+//#region src/compat/array/nth.d.ts
+/**
+ * Gets the element at index `n` of `array`. If `n` is negative, the nth element from the end is returned.
+ *
+ * @param array - The array to query.
+ * @param [n=0] - The index of the element to return.
+ * @return {T | undefined} Returns the nth element of `array`.
+ *
+ * @example
+ * nth([1, 2, 3], 1); // => 2
+ * nth([1, 2, 3], -1); // => 3
+ */
+declare function nth<T>(array: ArrayLike<T> | null | undefined, n?: number): T | undefined;
+//#endregion
+export { nth };