feat: 优化AI图片存储与访问流程

- 统一图片存储服务地址常量，返回完整可访问URL
- 图片上传接口支持匿名访问，并按日期创建存储目录
- ImageStoreTask 移除无用生成图片 Base64 字段，调整大字段存储配置
- 创建图片任务时补充 ModelId 信息
- 优先使用 Authorization 头部，避免覆盖已有认证信息
- 前端补充 Element Plus Descriptions 组件类型声明

Yi.Abp.Net8/module/ai-hub/Yi.Framework.AiHub.Application/Services/Chat/AiImageService.cs

@@ -98,7 +98,8 @@ public class AiImageService : ApplicationService
             ReferenceImagesUrl = new List<string>(),
             TaskStatus = TaskStatusEnum.Processing,
             UserId = userId,
-            TokenId = input.TokenId
+            TokenId = input.TokenId,
+            ModelId = input.ModelId
         };
 
         await _imageTaskRepository.InsertAsync(task);
@@ -146,6 +147,7 @@ public class AiImageService : ApplicationService
     /// <param name="base64Data">Base64图片数据（包含前缀如 data:image/png;base64,）</param>
     /// <returns>图片访问URL</returns>
     [HttpPost("ai-image/upload-base64")]
+    [AllowAnonymous]
     public async Task<string> UploadBase64ToUrlAsync([FromBody] string base64Data)
     {
         if (string.IsNullOrWhiteSpace(base64Data))
@@ -194,22 +196,31 @@ public class AiImageService : ApplicationService
             throw new UserFriendlyException("Base64格式无效");
         }
 
-        // 创建存储目录
-        var uploadPath = Path.Combine(_webHostEnvironment.ContentRootPath, "wwwroot", "ai-images");
+        // ==============================
+        // ✅ 按日期创建目录（yyyyMMdd）
+        // ==============================
+        var dateFolder = DateTime.Now.ToString("yyyyMMdd");
+        var uploadPath = Path.Combine(
+            _webHostEnvironment.ContentRootPath,
+            "wwwroot",
+            "ai-images",
+            dateFolder
+        );
+
         if (!Directory.Exists(uploadPath))
         {
             Directory.CreateDirectory(uploadPath);
         }
 
-        // 生成文件名并保存
+        // 保存文件
         var fileId = _guidGenerator.Create();
         var fileName = $"{fileId}{extension}";
         var filePath = Path.Combine(uploadPath, fileName);
 
         await File.WriteAllBytesAsync(filePath, imageBytes);
 
-        // 返回访问URL
-        return $"/ai-images/{fileName}";
+        // 返回包含日期目录的访问URL
+        return $"/wwwroot/ai-images/{dateFolder}/{fileName}";
     }
 
     /// <summary>