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/array/limitAsync.d.ts

@@ -0,0 +1,35 @@
+//#region src/array/limitAsync.d.ts
+/**
+ * Wraps an async function to limit the number of concurrent executions.
+ *
+ * This function creates a wrapper around an async callback that ensures at most
+ * `concurrency` number of executions can run simultaneously. Additional calls will
+ * wait until a slot becomes available.
+ *
+ * @template F - The type of the async function to wrap.
+ * @param callback The async function to wrap with concurrency control.
+ * @param concurrency Maximum number of concurrent executions allowed.
+ * @returns A wrapped version of the callback with concurrency limiting.
+ * @example
+ * const limitedFetch = limitAsync(async (url) => {
+ *   return await fetch(url);
+ * }, 3);
+ *
+ * // Only 3 fetches will run concurrently
+ * const urls = ['url1', 'url2', 'url3', 'url4', 'url5'];
+ * await Promise.all(urls.map(url => limitedFetch(url)));
+ *
+ * @example
+ * const processItem = async (item) => {
+ *   // Expensive async operation
+ *   return await heavyComputation(item);
+ * };
+ *
+ * const limitedProcess = limitAsync(processItem, 2);
+ * const items = [1, 2, 3, 4, 5];
+ * // At most 2 items will be processed concurrently
+ * await Promise.all(items.map(item => limitedProcess(item)));
+ */
+declare function limitAsync<F extends (...args: any[]) => Promise<any>>(callback: F, concurrency: number): F;
+//#endregion
+export { limitAsync };