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/compat/math/subtract.d.mts

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+//#region src/compat/math/subtract.d.ts
+/**
+ * Subtracts one number from another.
+ *
+ * If either of the numbers is `NaN`, the function returns `NaN`.
+ *
+ * @param value The first number. (minuend)
+ * @param other The second number.(subtrahend)
+ * @returns The difference of the two numbers, or `NaN` if any input is `NaN`.
+ *
+ * @example
+ * subtract(6, 3); // => 3
+ * subtract(6, NaN); // => NaN
+ * subtract(NaN, 3); // => NaN
+ */
+declare function subtract(value: number, other: number): number;
+//#endregion
+export { subtract };