feat(recycle-bin): 实现回收站功能

- 在数据库中添加逻辑删除字段和相关索引- 新增回收站相关实体类和接口
- 实现回收站列表查询、项目恢复、永久删除和清空回收站等功能
- 前端集成回收站接口，支持回收站页面操作

biji-houdaun/src/main/java/com/test/bijihoudaun/service/TrashService.java

@@ -0,0 +1,33 @@
+package com.test.bijihoudaun.service;
+
+import com.test.bijihoudaun.entity.TrashItemVo;
+
+import java.util.List;
+
+public interface TrashService {
+
+    /**
+     * 获取回收站中的所有项目
+     * @return 回收站项目列表
+     */
+    List<TrashItemVo> getTrashItems();
+
+    /**
+     * 恢复指定的回收站项目
+     * @param id 项目ID
+     * @param type 项目类型 ("note" 或 "group")
+     */
+    void restoreItem(String id, String type);
+
+    /**
+     * 永久删除指定的回收站项目
+     * @param id 项目ID
+     * @param type 项目类型 ("note" 或 "group")
+     */
+    void permanentlyDeleteItem(String id, String type);
+
+    /**
+     * 清空回收站
+     */
+    void cleanTrash();
+}

biji-houdaun/src/main/java/com/test/bijihoudaun/service/impl/TrashServiceImpl.java

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+package com.test.bijihoudaun.service.impl;
+
+import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
+import com.test.bijihoudaun.entity.Grouping;
+import com.test.bijihoudaun.entity.MarkdownFile;
+import com.test.bijihoudaun.entity.TrashItemVo;
+import com.test.bijihoudaun.mapper.GroupingMapper;
+import com.test.bijihoudaun.mapper.MarkdownFileMapper;
+import com.test.bijihoudaun.service.TrashService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+@Service
+public class TrashServiceImpl implements TrashService {
+
+    @Autowired
+    private MarkdownFileMapper markdownFileMapper;
+
+    @Autowired
+    private GroupingMapper groupingMapper;
+
+    @Override
+    public List<TrashItemVo> getTrashItems() {
+        // 查询已删除的笔记
+        List<TrashItemVo> deletedNotes = markdownFileMapper.selectList(new QueryWrapper<MarkdownFile>().eq("is_deleted", 1))
+                .stream()
+                .map(file -> {
+                    TrashItemVo vo = new TrashItemVo();
+                    vo.setId(String.valueOf(file.getId()));
+                    vo.setName(file.getTitle());
+                    vo.setType("note");
+                    vo.setDeletedAt(file.getDeletedAt());
+                    vo.setDeletedBy(String.valueOf(file.getDeletedBy()));
+                    return vo;
+                })
+                .collect(Collectors.toList());
+
+        // 查询已删除的分组
+        List<TrashItemVo> deletedGroups = groupingMapper.selectList(new QueryWrapper<Grouping>().eq("is_deleted", 1))
+                .stream()
+                .map(group -> {
+                    TrashItemVo vo = new TrashItemVo();
+                    vo.setId(String.valueOf(group.getId()));
+                    vo.setName(group.getGrouping());
+                    vo.setType("group");
+                    vo.setDeletedAt(group.getDeletedAt());
+                    vo.setDeletedBy(String.valueOf(group.getDeletedBy()));
+                    return vo;
+                })
+                .collect(Collectors.toList());
+
+        // 合并并返回
+        return Stream.concat(deletedNotes.stream(), deletedGroups.stream()).collect(Collectors.toList());
+    }
+
+    @Override
+    @Transactional
+    public void restoreItem(String id, String type) {
+        if ("note".equals(type)) {
+            MarkdownFile file = new MarkdownFile();
+            file.setId(Long.parseLong(id));
+            file.setIsDeleted(0);
+            file.setDeletedAt(null);
+            file.setDeletedBy(null);
+            markdownFileMapper.updateById(file);
+        } else if ("group".equals(type)) {
+            Grouping group = new Grouping();
+            group.setId(Long.parseLong(id));
+            group.setIsDeleted(0);
+            group.setDeletedAt(null);
+            group.setDeletedBy(null);
+            groupingMapper.updateById(group);
+        }
+    }
+
+    @Override
+    @Transactional
+    public void permanentlyDeleteItem(String id, String type) {
+        if ("note".equals(type)) {
+            markdownFileMapper.deleteById(Long.parseLong(id));
+        } else if ("group".equals(type)) {
+            // 删除分组时，也删除其下的所有笔记
+            groupingMapper.deleteById(Long.parseLong(id));
+            markdownFileMapper.delete(new QueryWrapper<MarkdownFile>().eq("grouping_id", id));
+        }
+    }
+
+    @Override
+    @Transactional
+    public void cleanTrash() {
+        markdownFileMapper.delete(new QueryWrapper<MarkdownFile>().eq("is_deleted", 1));
+        groupingMapper.delete(new QueryWrapper<Grouping>().eq("is_deleted", 1));
+    }
+}