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/map/reduce.mjs

@@ -0,0 +1,42 @@
+//#region src/map/reduce.ts
+/**
+* Reduces a Map to a single value by iterating through its entries and applying a callback function.
+*
+* This function iterates through all entries of the Map and applies the callback function to each entry,
+* accumulating the result. If an initial value is provided, it is used as the starting accumulator value.
+* If no initial value is provided and the Map is empty, a TypeError is thrown.
+*
+* @template K - The type of keys in the Map.
+* @template V - The type of values in the Map.
+* @param map - The Map to reduce.
+* @param callback - A function that processes each entry and updates the accumulator.
+* @param [initialValue] - The initial value for the accumulator. If not provided, the first value in the Map is used.
+* @returns The final accumulated value.
+* @throws {TypeError} If the Map is empty and no initial value is provided.
+*
+* @example
+* const map = new Map([
+*   ['a', 1],
+*   ['b', 2],
+*   ['c', 3]
+* ]);
+* const result = reduce(map, (acc, value) => acc + value, 0);
+* // result will be: 6
+*
+* @example
+* const map = new Map([
+*   ['a', 10],
+*   ['b', 20]
+* ]);
+* const result = reduce(map, (acc, value) => acc + value);
+* // result will be: 30 (starts with first value 10)
+*/
+function reduce(map, callback, initialValue) {
+	if (initialValue == null && map.size === 0) throw new TypeError("Reduce of empty map with no initial value");
+	let accumulator = initialValue;
+	for (const [key, value] of map) if (accumulator == null) accumulator = value;
+	else accumulator = callback(accumulator, value, key, map);
+	return accumulator;
+}
+//#endregion
+export { reduce };