refactor(codegen): 优化代码结构和导入

- 更新了导入语句，使用 org.springframework.lang.Nullable 替代 javax.annotation.Nullable
- 优化了代码格式，提高了可读性
- 在 SpringApiSdkCodegenProcessor 中添加了必要的导入语句

Author: fengwuxp

annotation-processor/src/main/java/com/wuxp/codegen/meta/annotations/factories/SpringApiSdkCodegenProcessor.java

@@ -9,7 +9,11 @@
 import com.wuxp.codegen.core.util.CodegenFileUtils;
 import com.wuxp.codegen.starter.LoongCodeGenerator;
 
-import javax.annotation.processing.*;
+import javax.annotation.processing.AbstractProcessor;
+import javax.annotation.processing.Messager;
+import javax.annotation.processing.ProcessingEnvironment;
+import javax.annotation.processing.RoundEnvironment;
+import javax.annotation.processing.SupportedAnnotationTypes;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.TypeElement;
 import javax.tools.Diagnostic;
@@ -60,7 +64,8 @@ public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment
                 Class<? extends Annotation> entityAnnotationType = ClassLoaderUtils.loadClass(className);
                 processAnnotations(roundEnv.getElementsAnnotatedWith(entityAnnotationType), codeGenerators);
             } catch (ClassNotFoundException e) {
-                this.processingEnv.getMessager().printMessage(Diagnostic.Kind.NOTE, String.format("%s  can't found class %s", getClass().getSimpleName(), className));
+                this.processingEnv.getMessager().printMessage(Diagnostic.Kind.NOTE, String.format("%s  can't found class %s",
+                        getClass().getSimpleName(), className));
             }
         }
         return false;

loong-quick/codegen-server/src/main/java/com/wuxp/codegen/server/task/CodegenTaskService.java

@@ -1,6 +1,7 @@
 package com.wuxp.codegen.server.task;
 
-import javax.annotation.Nullable;
+
+import org.springframework.lang.Nullable;
 
 /**
  * 代码生成任务服务

loong-quick/codegen-server/src/main/java/com/wuxp/codegen/server/vcs/SourceCodeRepositoryAccessProperties.java

@@ -3,8 +3,8 @@
 
 import com.wuxp.codegen.server.enums.SourcecodeRepositoryType;
 import org.springframework.core.Ordered;
+import org.springframework.lang.Nullable;
 
-import javax.annotation.Nullable;
 
 /**
  * 访问源代码仓库访问属性