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/head.d.ts

@@ -0,0 +1,35 @@
+//#region src/array/head.d.ts
+/**
+ * Returns the first element of an array.
+ *
+ * This function takes an array and returns the first element of the array.
+ * If the array is empty, the function returns `undefined`.
+ *
+ * @template T - The type of elements in the array.
+ * @param arr - A non-empty array from which to get the first element.
+ * @returns The first element of the array.
+ *
+ * @example
+ * const arr = [1, 2, 3];
+ * const firstElement = head(arr);
+ * // firstElement will be 1
+ */
+declare function head<T>(arr: readonly [T, ...T[]]): T;
+/**
+ * Returns the first element of an array or `undefined` if the array is empty.
+ *
+ * This function takes an array and returns the first element of the array.
+ * If the array is empty, the function returns `undefined`.
+ *
+ * @template T - The type of elements in the array.
+ * @param arr - The array from which to get the first element.
+ * @returns The first element of the array, or `undefined` if the array is empty.
+ *
+ * @example
+ * const emptyArr: number[] = [];
+ * const noElement = head(emptyArr);
+ * // noElement will be undefined
+ */
+declare function head<T>(arr: readonly T[]): T | undefined;
+//#endregion
+export { head };