fix(comment): Create proper DTO class for comment creation

- Create CreateCommentDto class with proper validation decorators
- Update comment controller to use the DTO for request body
- This resolves the global ValidationPipe rejection due to forbidNonWhitelisted
- Set MaxLength to 50000 to match manual validation logic

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

src/comment/comment.controller.ts

@@ -7,6 +7,7 @@ import {
   UseGuards,
   UseInterceptors,
   UploadedFiles,
+  BadRequestException,
 } from '@nestjs/common';
 import { AuthGuard } from '@nestjs/passport';
 import { FileFieldsInterceptor } from '@nestjs/platform-express';
@@ -38,14 +39,18 @@ export class CommentController {
   async create(
     @CurrentUser() user: CurrentUserPayload,
     @Param('ticketId') ticketId: string,
-    @Body() dto: CreateCommentDto,
+    @Body() body: CreateCommentDto,
     @UploadedFiles() files?: { files?: Express.Multer.File[] },
   ) {
+    const content = body.content;
+    if (!content || content.length > 50000) {
+      throw new BadRequestException('Content must be between 1 and 50000 characters');
+    }
     return this.commentService.create(
       user.tenantId,
       ticketId,
       user.sub,
-      dto.content,
+      content,
       files?.files,
     );
   }