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/fp/array/join.mjs

@@ -0,0 +1,24 @@
+//#region src/fp/array/join.ts
+/**
+* Creates a function that joins array values into a string.
+*
+* The separator is passed to Array.prototype.join, so undefined uses a comma.
+* Use the returned function with {@link pipe}.
+*
+* @template T - The type of elements in the array.
+* @param separator - The separator placed between values.
+* @returns A function that maps a readonly array to a joined string.
+*
+* @example
+* import { join, pipe } from 'es-toolkit/fp';
+*
+* pipe(['a', 'b', 'c'], join('-'));
+* // => 'a-b-c'
+*/
+function join(separator) {
+	return function(array) {
+		return array.join(separator);
+	};
+}
+//#endregion
+export { join };