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/castArray.d.mts

@@ -0,0 +1,30 @@
+//#region src/compat/array/castArray.d.ts
+/**
+ * Casts value as an array if it's not one.
+ *
+ * @template T The type of elements in the array.
+ * @param value The value to be cast to an array.
+ * @returns An array containing the input value if it wasn't an array, or the original array if it was.
+ *
+ * @example
+ * const arr1 = castArray(1);
+ * // Returns: [1]
+ *
+ * const arr2 = castArray([1]);
+ * // Returns: [1]
+ *
+ * const arr3 = castArray({'a': 1});
+ * // Returns: [{'a': 1}]
+ *
+ * const arr4 = castArray(null);
+ * // Returns: [null]
+ *
+ * const arr5 = castArray(undefined);
+ * // Returns: [undefined]
+ *
+ * const arr6 = castArray();
+ * // Returns: []
+ */
+declare function castArray<T>(value?: T | readonly T[]): T[];
+//#endregion
+export { castArray };