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/object/merge.d.mts

@@ -0,0 +1,44 @@
+//#region src/object/merge.d.ts
+/**
+ * Merges the properties of the source object into the target object.
+ *
+ * This function performs a deep merge, meaning nested objects and arrays are merged recursively.
+ * If a property in the source object is an array or an object and the corresponding property in the target object is also an array or object, they will be merged.
+ * If a property in the source object is undefined, it will not overwrite a defined property in the target object.
+ *
+ * Note that this function mutates the target object.
+ *
+ * @param target - The target object into which the source object properties will be merged. This object is modified in place.
+ * @param source - The source object whose properties will be merged into the target object.
+ * @returns The updated target object with properties from the source object merged in.
+ *
+ * @template T - Type of the target object.
+ * @template S - Type of the source object.
+ *
+ * @example
+ * const target = { a: 1, b: { x: 1, y: 2 } };
+ * const source = { b: { y: 3, z: 4 }, c: 5 };
+ *
+ * const result = merge(target, source);
+ * console.log(result);
+ * // Output: { a: 1, b: { x: 1, y: 3, z: 4 }, c: 5 }
+ *
+ * @example
+ * const target = { a: [1, 2], b: { x: 1 } };
+ * const source = { a: [3], b: { y: 2 } };
+ *
+ * const result = merge(target, source);
+ * console.log(result);
+ * // Output: { a: [3, 2], b: { x: 1, y: 2 } }
+ *
+ * @example
+ * const target = { a: null };
+ * const source = { a: [1, 2, 3] };
+ *
+ * const result = merge(target, source);
+ * console.log(result);
+ * // Output: { a: [1, 2, 3] }
+ */
+declare function merge<T extends Record<PropertyKey, any>, S extends Record<PropertyKey, any>>(target: T, source: S): T & S;
+//#endregion
+export { merge };