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.mjs

@@ -0,0 +1,16 @@
+import { updateWith } from "./updateWith.mjs";
+//#region src/compat/object/update.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.
+*/
+function update(obj, path, updater) {
+	return updateWith(obj, path, updater, () => void 0);
+}
+//#endregion
+export { update };