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/util/toPlainObject.mjs

@@ -0,0 +1,33 @@
+import { keysIn } from "../object/keysIn.mjs";
+//#region src/compat/util/toPlainObject.ts
+/**
+* Converts value to a plain object flattening inherited enumerable string keyed properties of value to own properties of the plain object.
+*
+* @param value The value to convert.
+* @returns Returns the converted plain object.
+*
+* @example
+* function Foo() {
+*   this.b = 2;
+* }
+* Foo.prototype.c = 3;
+* toPlainObject(new Foo()); // { b: 2, c: 3 }
+*/
+function toPlainObject(value) {
+	const plainObject = {};
+	const valueKeys = keysIn(value);
+	for (let i = 0; i < valueKeys.length; i++) {
+		const key = valueKeys[i];
+		const objValue = value[key];
+		if (key === "__proto__") Object.defineProperty(plainObject, key, {
+			configurable: true,
+			enumerable: true,
+			value: objValue,
+			writable: true
+		});
+		else plainObject[key] = objValue;
+	}
+	return plainObject;
+}
+//#endregion
+export { toPlainObject };