feat: add ticket comments, file attachments, mention notifications

- Comment module with CRUD and file upload via multer
- @mention parsing with user notification
- Assignment notification on ticket update
- Notification service enhanced with ticketId linking
- ServeStaticModule for uploaded files

src/app.module.ts

@@ -2,6 +2,8 @@ import { Module } from '@nestjs/common';
 import { ConfigModule } from '@nestjs/config';
 import { APP_FILTER, APP_GUARD, APP_INTERCEPTOR } from '@nestjs/core';
 import { ThrottlerModule, ThrottlerGuard } from '@nestjs/throttler';
+import { ServeStaticModule } from '@nestjs/serve-static';
+import { join } from 'path';
 import { HealthModule } from './health/health.module';
 import { PrismaModule } from './prisma/prisma.module';
 import { AuthModule } from './auth/auth.module';
@@ -28,6 +30,7 @@ import { SchedulerModule } from './scheduler/scheduler.module';
 import { AccountingModule } from './accounting/accounting.module';
 import { PayrollModule } from './payroll/payroll.module';
 import { RoleModule } from './role/role.module';
+import { CommentModule } from './comment/comment.module';
 import { GlobalExceptionFilter } from './common/filters/http-exception.filter';
 import { ResponseInterceptor } from './common/interceptors/response.interceptor';
 import { PermissionsGuard } from './common/guards/permissions.guard';
@@ -69,6 +72,11 @@ import { AccessGuard } from './common/guards/access.guard';
     AccountingModule,
     PayrollModule,
     RoleModule,
+    CommentModule,
+    ServeStaticModule.forRoot({
+      rootPath: join(__dirname, '..', 'uploads'),
+      serveRoot: '/uploads',
+    }),
   ],
   providers: [
     { provide: APP_FILTER, useClass: GlobalExceptionFilter },