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/predicate/isNull.mjs

@@ -0,0 +1,17 @@
+//#region src/compat/predicate/isNull.ts
+/**
+* Checks if `value` is `null`.
+*
+* @param value - The value to check.
+* @returns Returns `true` if `value` is `null`, else `false`.
+*
+* @example
+* isNull(null); // true
+* isNull(undefined); // false
+* isNull(0); // false
+*/
+function isNull(value) {
+	return value === null;
+}
+//#endregion
+export { isNull };