fix checking validity when solving

index.js

@@ -35,7 +35,7 @@ app.use("/solved", async (req, res) => {
     res.send(readdirSync("./data").length);
 });
 app.post("/solve", async (req, res) => {
-    let file = "./data/" + req.body.uuid + "/image.png";
+    let file = Bun.file("./data/" + req.body.uuid + "/image.png");
     if(await file.exists() && (req.body.answer.length == 4 || req.body.answer.length == 5)) {
         await Bun.write("./data/" + req.body.uuid + "/answer.txt", req.body.answer);
     }