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-abstract/helpers/reduce.js

@@ -0,0 +1,9 @@
+'use strict';
+
+module.exports = function reduce(arr, fn, init) {
+	var acc = init;
+	for (var i = 0; i < arr.length; i += 1) {
+		acc = fn(acc, arr[i], i);
+	}
+	return acc;
+};