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/indexOf.d.ts

@@ -0,0 +1,21 @@
+//#region src/compat/array/indexOf.d.ts
+/**
+ * Finds the index of the first occurrence of a value in an array.
+ *
+ * This method is similar to `Array.prototype.indexOf`, but it also finds `NaN` values.
+ * It uses strict equality (`===`) to compare elements.
+ *
+ * @template T - The type of elements in the array.
+ * @param array - The array to search.
+ * @param searchElement - The value to search for.
+ * @param [fromIndex] - The index to start the search at.
+ * @returns The index (zero-based) of the first occurrence of the value in the array, or `-1` if the value is not found.
+ *
+ * @example
+ * const array = [1, 2, 3, NaN];
+ * indexOf(array, 3); // => 2
+ * indexOf(array, NaN); // => 3
+ */
+declare function indexOf<T>(array: ArrayLike<T> | null | undefined, searchElement: T, fromIndex?: number): number;
+//#endregion
+export { indexOf };