feat(image): 实现 Markdown 图片文件名同步

- 新增 ImageName 实体类和对应的 Mapper- 在 MarkdownFileService 中添加图片文件名同步方法
- 优化 HomePage 组件，支持实时预览 Markdown 内容
- 新增 MarkdownImageExtractor 工具类，用于提取 Markdown 中的图片文件名

biji-houdaun/src/main/java/com/test/bijihoudaun/config/AsyncConfig.java

@@ -0,0 +1,24 @@
+package com.test.bijihoudaun.config;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.scheduling.annotation.EnableAsync;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+
+import java.util.concurrent.Executor;
+
+@Configuration
+@EnableAsync
+public class AsyncConfig {
+
+    @Bean("imageNameSyncExecutor")
+    public Executor imageNameSyncExecutor() {
+        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
+        executor.setCorePoolSize(5);
+        executor.setMaxPoolSize(10);
+        executor.setQueueCapacity(100);
+        executor.setThreadNamePrefix("imageNameSync-");
+        executor.initialize();
+        return executor;
+    }
+}