feat: add initial project configuration and smoke tests

- Created pnpm workspace configuration to manage packages.
- Added a placeholder .gitkeep file in the scripts directory.
- Implemented a smoke test script to validate core API and web endpoints.
- Established TypeScript base configuration for consistent compilation settings.
- Introduced Turbo configuration for task management and build processes.

packages/api/src/prisma/prisma.service.ts

@@ -0,0 +1,33 @@
+import { Injectable, OnModuleInit, OnModuleDestroy } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import { PrismaClient } from '../generated/prisma/client';
+import { PrismaPg } from '@prisma/adapter-pg';
+
+/**
+ * NestJS-managed Prisma service for Prisma 7.
+ *
+ * Follows the official NestJS + Prisma 7 recipe:
+ * - Uses `prisma-client` generator with `moduleFormat = "cjs"`
+ * - Extends PrismaClient directly for full type-safe API access
+ * - Uses PrismaPg driver adapter with connectionString
+ *
+ * Usage in feature modules:
+ *   constructor(private readonly prisma: PrismaService) {}
+ *   await this.prisma.placeholder.findMany();
+ */
+@Injectable()
+export class PrismaService extends PrismaClient implements OnModuleInit, OnModuleDestroy {
+  constructor(configService: ConfigService) {
+    const databaseUrl = configService.getOrThrow<string>('DATABASE_URL');
+    const adapter = new PrismaPg({ connectionString: databaseUrl });
+    super({ adapter });
+  }
+
+  async onModuleInit(): Promise<void> {
+    await this.$connect();
+  }
+
+  async onModuleDestroy(): Promise<void> {
+    await this.$disconnect();
+  }
+}