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/function/nthArg.d.ts

@@ -0,0 +1,19 @@
+//#region src/compat/function/nthArg.d.ts
+/**
+ * Creates a function that gets the argument at index `n`. If `n` is negative, the nth argument from the end is returned.
+ *
+ * @param [n=0] - The index of the argument to return.
+ * @returns Returns the new function.
+ *
+ * @example
+ * var func = nthArg(1);
+ * func('a', 'b', 'c', 'd');
+ * // => 'b'
+ *
+ * var func = nthArg(-2);
+ * func('a', 'b', 'c', 'd');
+ * // => 'c'
+ */
+declare function nthArg(n?: number): (...args: any[]) => any;
+//#endregion
+export { nthArg };