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/object/update.d.ts

@@ -0,0 +1,15 @@
+import { PropertyPath } from "../_internal/PropertyPath.js";
+
+//#region src/compat/object/update.d.ts
+/**
+ * Updates the value at the specified path of the given object using an updater function.
+ * If any part of the path does not exist, it will be created.
+ *
+ * @param obj - The object to modify.
+ * @param path - The path of the property to update.
+ * @param updater - The function to produce the updated value.
+ * @returns The modified object.
+ */
+declare function update(obj: object, path: PropertyPath, updater: (value: any) => any): any;
+//#endregion
+export { update };