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/union.d.mts

@@ -0,0 +1,31 @@
+//#region src/compat/array/union.d.ts
+/**
+ * This function takes multiple arrays and returns a new array containing only the unique values
+ * from all input arrays, preserving the order of their first occurrence.
+ *
+ * @template T - The type of elements in the arrays.
+ * @param arrays - The arrays to inspect.
+ * @returns Returns the new array of combined unique values.
+ *
+ * @example
+ * // Returns [2, 1]
+ * union([2], [1, 2]);
+ *
+ * @example
+ * // Returns [2, 1, 3]
+ * union([2], [1, 2], [2, 3]);
+ *
+ * @example
+ * // Returns [1, 3, 2, [5], [4]] (does not deeply flatten nested arrays)
+ * union([1, 3, 2], [1, [5]], [2, [4]]);
+ *
+ * @example
+ * // Returns [0, 2, 1] (ignores non-array values like 3 and { '0': 1 })
+ * union([0], 3, { '0': 1 }, null, [2, 1]);
+ * @example
+ * // Returns [0, 'a', 2, 1] (treats array-like object { 0: 'a', length: 1 } as a valid array)
+ * union([0], { 0: 'a', length: 1 }, [2, 1]);
+ */
+declare function union<T>(...arrays: Array<ArrayLike<T> | null | undefined>): T[];
+//#endregion
+export { union };