Fix mobile validation, cascade delete for businesses/categories, and DB error handling.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/main.ts

@@ -2,6 +2,7 @@ import 'reflect-metadata';
 import { ValidationPipe } from '@nestjs/common';
 import { NestFactory } from '@nestjs/core';
 import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
+import { TypeOrmExceptionFilter } from './common/filters/typeorm-exception.filter';
 import { AppModule } from './app.module';
 
 function configureCors(app: Awaited<ReturnType<typeof NestFactory.create>>) {
@@ -26,6 +27,7 @@ async function bootstrap() {
       whitelist: true,
     }),
   );
+  app.useGlobalFilters(new TypeOrmExceptionFilter());
 
   const swaggerConfig = new DocumentBuilder()
     .setTitle('Montime API')