fix: 修复微信头像上传到服务器功能

- auth-modal.vue: 登录前先上传微信临时头像到服务器
- uploadAvatar接口支持临时上传(temp参数)
- 数据库avatar_url存储服务器路径而非临时路径

src/main/java/xuan/controller/UserController.java

@@ -369,7 +369,8 @@ public class UserController {
     @PostMapping("/uploadAvatar")
     public Map<String, Object> uploadAvatar(
             @RequestParam("file") MultipartFile file,
-            @RequestParam("userId") String userId) {
+            @RequestParam(value = "userId", required = false) String userId,
+            @RequestParam(value = "temp", required = false) String temp) {
         Map<String, Object> result = new HashMap<>();
         try {
             if (file.isEmpty()) {
@@ -385,7 +386,7 @@ public class UserController {
             }
             
             String originalFilename = file.getOriginalFilename();
-            String extension = "";
+            String extension = ".jpg";
             if (originalFilename != null && originalFilename.contains(".")) {
                 extension = originalFilename.substring(originalFilename.lastIndexOf("."));
             }
@@ -396,16 +397,19 @@ public class UserController {
             
             String avatarUrl = "/uploads/avatars/" + filename;
             
-            UserInfo user = userInfoService.updateAvatarUrl(userId, avatarUrl);
-            if (user != null) {
-                Map<String, Object> data = new HashMap<>();
-                data.put("avatarUrl", avatarUrl);
-                result.put("success", true);
-                result.put("data", data);
-            } else {
-                result.put("success", false);
-                result.put("error", "用户不存在");
+            if (userId != null && !userId.isEmpty() && !"true".equals(temp)) {
+                UserInfo user = userInfoService.updateAvatarUrl(userId, avatarUrl);
+                if (user == null) {
+                    result.put("success", false);
+                    result.put("error", "用户不存在");
+                    return result;
+                }
             }
+            
+            Map<String, Object> data = new HashMap<>();
+            data.put("avatarUrl", avatarUrl);
+            result.put("success", true);
+            result.put("data", data);
         } catch (IOException e) {
             result.put("success", false);
             result.put("error", "文件上传失败: " + e.getMessage());