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/lastIndexOf.d.ts

@@ -0,0 +1,23 @@
+//#region src/compat/array/lastIndexOf.d.ts
+/**
+ * Gets the index at which the last occurrence of value is found in array.
+ *
+ * @template T
+ * @param array - The array to inspect.
+ * @param value - The value to search for.
+ * @param [fromIndex] - The index to search from or true to search from the end.
+ * @returns Returns the index of the matched value, else -1.
+ *
+ * @example
+ * lastIndexOf([1, 2, 1, 2], 2);
+ * // => 3
+ *
+ * lastIndexOf([1, 2, 1, 2], 2, 2);
+ * // => 1
+ *
+ * lastIndexOf([1, 2, 1, 2], 2, true);
+ * // => 1
+ */
+declare function lastIndexOf<T>(array: ArrayLike<T> | null | undefined, searchElement: T, fromIndex?: true | number): number;
+//#endregion
+export { lastIndexOf };