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/median.d.ts

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+//#region src/math/median.d.ts
+/**
+ * Calculates the median of an array of numbers.
+ *
+ * The median is the middle value of a sorted array.
+ * If the array has an odd number of elements, the median is the middle value.
+ * If the array has an even number of elements, it returns the average of the two middle values.
+ *
+ * If the array is empty, this function returns `NaN`.
+ *
+ * @param nums - An array of numbers to calculate the median.
+ * @returns The median of all the numbers in the array.
+ *
+ * @example
+ * const arrayWithOddNumberOfElements = [1, 2, 3, 4, 5];
+ * const result = median(arrayWithOddNumberOfElements);
+ * // result will be 3
+ *
+ * @example
+ * const arrayWithEvenNumberOfElements = [1, 2, 3, 4];
+ * const result = median(arrayWithEvenNumberOfElements);
+ * // result will be 2.5
+ */
+declare function median(nums: readonly number[]): number;
+//#endregion
+export { median };