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/keyBy.d.mts

@@ -0,0 +1,21 @@
+//#region src/fp/array/keyBy.d.ts
+/**
+ * Creates a function that indexes values by a derived key.
+ *
+ * The key selector receives each value, index, and full input array. When multiple values
+ * produce the same key, the last value wins, matching the main {@link keyBy} behavior.
+ *
+ * @template T - The type of elements in the array.
+ * @template K - The property-key type produced by the selector.
+ * @param getKey - Called with each value, index, and array to produce an object key.
+ * @returns A function that maps a readonly array to an object keyed by the derived keys.
+ *
+ * @example
+ * import { keyBy, pipe } from 'es-toolkit/fp';
+ *
+ * pipe([{ id: 'a', value: 1 }, { id: 'b', value: 2 }], keyBy(item => item.id));
+ * // => { a: { id: 'a', value: 1 }, b: { id: 'b', value: 2 } }
+ */
+declare function keyBy<T, K extends PropertyKey>(getKey: (item: T, index: number, array: readonly T[]) => K): (array: readonly T[]) => Record<K, T>;
+//#endregion
+export { keyBy };