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/isInteger.d.mts

@@ -0,0 +1,18 @@
+//#region src/compat/predicate/isInteger.d.ts
+/**
+ * Checks if `value` is an integer.
+ *
+ * This function can also serve as a type predicate in TypeScript, narrowing the type of the argument to `number`.
+ *
+ * @param value - The value to check
+ * @returns `true` if `value` is integer, otherwise `false`.
+ *
+ * @example
+ * isInteger(3); // Returns: true
+ * isInteger(Infinity); // Returns: false
+ * isInteger('3'); // Returns: false
+ * isInteger([]); // Returns: false
+ */
+declare function isInteger(value?: any): boolean;
+//#endregion
+export { isInteger };