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/isSymbol.mjs

@@ -0,0 +1,20 @@
+//#region src/compat/predicate/isSymbol.ts
+/**
+* Check whether a value is a symbol.
+*
+* This function can also serve as a type predicate in TypeScript, narrowing the type of the argument to `symbol`.
+*
+* @param value The value to check.
+* @returns Returns `true` if `value` is a symbol, else `false`.
+* @example
+* isSymbol(Symbol.iterator);
+* // => true
+*
+* isSymbol('abc');
+* // => false
+*/
+function isSymbol(value) {
+	return typeof value === "symbol" || value instanceof Symbol;
+}
+//#endregion
+export { isSymbol };