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/fp/array/unionWith.d.mts

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+//#region src/fp/array/unionWith.d.ts
+/**
+ * Creates a function that returns unique values using a custom equality function.
+ *
+ * Values from the piped array are considered before values from secondArray. The equality
+ * function decides whether two values represent the same item.
+ *
+ * @template T - The type of elements in the arrays.
+ * @param secondArray - Values to include after the piped array.
+ * @param areItemsEqual - Returns true when two values are equal.
+ * @returns A function that maps a readonly array to its union with secondArray.
+ *
+ * @example
+ * import { pipe, unionWith } from 'es-toolkit/fp';
+ *
+ * pipe([{ id: 1 }], unionWith([{ id: 1 }, { id: 2 }], (a, b) => a.id === b.id));
+ * // => [{ id: 1 }, { id: 2 }]
+ */
+declare function unionWith<T>(secondArray: readonly T[], areItemsEqual: (item: T, other: T) => boolean): (array: readonly T[]) => T[];
+//#endregion
+export { unionWith };