fix: IDeserializer并非线程安全

YaeBlog.Core/Models/BlogEssay.cs

@@ -4,6 +4,8 @@ public class BlogEssay
 {
     public required string Title { get; init; }
 
+    public required string FileName { get; init; }
+
     public required DateTime PublishTime { get; init; }
 
     public List<string> Tags { get; } = [];

YaeBlog.Core/Models/MarkdownMetadata.cs

@@ -6,5 +6,5 @@ public class MarkdownMetadata
 
     public DateTime? Date { get; set; }
 
-    public List<string> Tags { get; set; } = [];
+    public List<string>? Tags { get; set; }
 }