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/array/flatMapDeep.mjs

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+import { flatMapDepth } from "./flatMapDepth.mjs";
+//#region src/compat/array/flatMapDeep.ts
+/**
+* Creates a flattened array of values by running each element through iteratee and recursively flattening the mapped results.
+*
+* @template T, R
+* @param collection - The array or object to iterate over.
+* @param [iteratee] - The function that produces the new array elements.
+* @returns A new array that has been deeply flattened.
+*
+* @example
+* flatMapDeep([1, 2, 3], n => [[n, n]]);
+* // => [1, 1, 2, 2, 3, 3]
+*/
+function flatMapDeep(collection, iteratee) {
+	return flatMapDepth(collection, iteratee, Infinity);
+}
+//#endregion
+export { flatMapDeep };