fix(guild): validate channel create payload and return 400

src/channels/channels.service.ts

@@ -1,4 +1,4 @@
-import { Injectable } from '@nestjs/common';
+import { BadRequestException, Injectable } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import { Repository } from 'typeorm';
 import { Channel } from '../entities/channel.entity';
@@ -26,9 +26,14 @@ export class ChannelsService {
   }
 
   create(input: Partial<Channel>) {
+    const guildId = String(input.guildId ?? '').trim();
+    const name = String(input.name ?? '').trim();
+    if (!guildId) throw new BadRequestException('guildId is required');
+    if (!name) throw new BadRequestException('name is required');
+
     const channel = this.channelRepo.create({
-      guildId: String(input.guildId ?? ''),
-      name: String(input.name ?? ''),
+      guildId,
+      name,
       kind: input.kind === 'announcement' ? 'announcement' : 'text',
       isPrivate: Boolean(input.isPrivate),
       lastSeq: 0,