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/math/sum.js

@@ -0,0 +1,21 @@
+//#region src/math/sum.ts
+/**
+* Calculates the sum of an array of numbers.
+*
+* This function takes an array of numbers and returns the sum of all the elements in the array.
+*
+* @param nums - An array of numbers to be summed.
+* @returns The sum of all the numbers in the array.
+*
+* @example
+* const numbers = [1, 2, 3, 4, 5];
+* const result = sum(numbers);
+* // result will be 15
+*/
+function sum(nums) {
+	let result = 0;
+	for (let i = 0; i < nums.length; i++) result += nums[i];
+	return result;
+}
+//#endregion
+exports.sum = sum;