[fix] errors with default empty steam users + loading process

src/app/(main)/preference/path/page.tsx

@@ -10,7 +10,7 @@ export default function Page() {
       <p>游戏路径：{steam.state.cs2Dir}</p>
       <p>Steam路径有效：{steam.state.steamDirValid ? "是" : "否"}</p>
       <p>游戏路径有效：{steam.state.cs2DirValid ? "是" : "否"}</p>
-      <p>Steam账号：{steam.currentUser().accountName}</p>
+      <p>Steam账号：{steam.currentUser()?.accountName || " "}</p>
     </div>
   )
 }

src/app/prepare/page.tsx

@@ -39,7 +39,7 @@ export default function Page() {
             steam.setCsDir(e.target.value)
           }}
         />
-        <p>当前用户64位SteamID：{steam.currentUser().steamID64}</p>
+        <p>当前用户64位SteamID：{steam.currentUser()?.steamID64}</p>
       </div>
     </div>
   )