add: 渲染前处理器和渲染后处理器

YaeBlog.Core/Abstractions/IPostRenderProcessor.cs

@@ -0,0 +1,10 @@
+using YaeBlog.Core.Models;
+
+namespace YaeBlog.Core.Abstractions;
+
+public interface IPostRenderProcessor
+{
+    BlogEssay Process(BlogEssay essay);
+
+    string Name { get; }
+}

YaeBlog.Core/Abstractions/IPreRenderProcessor.cs

@@ -0,0 +1,10 @@
+using YaeBlog.Core.Models;
+
+namespace YaeBlog.Core.Abstractions;
+
+public interface IPreRenderProcessor
+{
+    BlogContent Process(BlogContent content);
+
+    string Name { get; }
+}