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/workbox-precaching/utils/getCacheKeyForURL.d.ts

@@ -0,0 +1,14 @@
+import { PrecacheRouteOptions } from '../_types.js';
+import '../_version.js';
+/**
+ * This function will take the request URL and manipulate it based on the
+ * configuration options.
+ *
+ * @param {string} url
+ * @param {Object} options
+ * @return {string} Returns the URL in the cache that matches the request,
+ * if possible.
+ *
+ * @private
+ */
+export declare const getCacheKeyForURL: (url: string, options: PrecacheRouteOptions) => string | void;