feat: 知识点软删除 + 批量删除接口

- DELETE /knowledge-items/:id 软删除（设 deletedAt）
- POST /knowledge-items/batch-delete 批量软删除
- softDelete 校验归属权 + 自动更新父KB的itemCount

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/modules/knowledge-items/knowledge-items.controller.ts

@@ -1,4 +1,4 @@
-import { Controller, Get, Post, Patch, Body, Param, Query } from '@nestjs/common';
+import { Controller, Get, Post, Patch, Delete, Body, Param, Query, HttpCode, HttpStatus } from '@nestjs/common';
 import { ApiTags, ApiOperation, ApiResponse } from '@nestjs/swagger';
 import { KnowledgeItemsService } from './knowledge-items.service';
 import { CurrentUser } from '../../common/decorators/current-user.decorator';
@@ -32,4 +32,20 @@ export class KnowledgeItemsController {
   async update(@Param('id') id: string, @Body() body: any) {
     return this.service.update(id, body);
   }
+
+  @Delete(':id')
+  @HttpCode(HttpStatus.OK)
+  @ApiOperation({ summary: '软删除知识点' })
+  async delete(@CurrentUser() user: UserPayload, @Param('id') id: string) {
+    await this.service.softDelete(id, String(user?.id || 'anonymous'));
+    return { success: true, message: '已删除' };
+  }
+
+  @Post('batch-delete')
+  @HttpCode(HttpStatus.OK)
+  @ApiOperation({ summary: '批量软删除知识点' })
+  async batchDelete(@CurrentUser() user: UserPayload, @Body() body: { ids: string[] }) {
+    const count = await this.service.batchSoftDelete(body.ids || [], String(user?.id || 'anonymous'));
+    return { success: true, message: `已删除 ${count} 个知识点`, count };
+  }
 }

src/modules/knowledge-items/knowledge-items.repository.ts

@@ -50,4 +50,19 @@ export class KnowledgeItemsRepository {
       data: dto,
     });
   }
+
+  async softDelete(id: string) {
+    const item = await this.prisma.knowledgeItem.update({
+      where: { id },
+      data: { deletedAt: new Date() },
+    });
+
+    // 更新知识库 itemCount
+    await this.prisma.knowledgeBase.update({
+      where: { id: item.knowledgeBaseId },
+      data: { itemCount: { decrement: 1 } },
+    });
+
+    return item;
+  }
 }

src/modules/knowledge-items/knowledge-items.service.ts

@@ -1,4 +1,4 @@
-import { Injectable, NotFoundException } from '@nestjs/common';
+import { Injectable, NotFoundException, ForbiddenException } from '@nestjs/common';
 import { KnowledgeItemsRepository } from './knowledge-items.repository';
 
 @Injectable()
@@ -24,4 +24,25 @@ export class KnowledgeItemsService {
     if (!item) throw new NotFoundException('知识点不存在');
     return item;
   }
+
+  async softDelete(id: string, userId: string) {
+    const item = await this.repository.findById(id);
+    if (!item) throw new NotFoundException('知识点不存在');
+    if (item.userId !== userId) throw new ForbiddenException('无权操作');
+    return this.repository.softDelete(id);
+  }
+
+  async batchSoftDelete(ids: string[], userId: string) {
+    if (!ids.length) return 0;
+    let count = 0;
+    for (const id of ids) {
+      try {
+        await this.softDelete(id, userId);
+        count++;
+      } catch {
+        // 跳过不存在的或无权操作的
+      }
+    }
+    return count;
+  }
 }