fix: address deployment memory issues

[fabio-nettis]

Description

Recent deployment monitoring has shown that we waste a lot of unnecessary memory by not properly re-using a single Prisma instance but creating a new one for each route handler. Following fix has been implemented:

// utils/database.ts

import { PrismaClient } from "@prisma/client";

const globalForPrisma = globalThis as unknown as { db: PrismaClient };

// prevent hot reloading from creating new instances of PrismaClient
export const db = globalForPrisma.db || new PrismaClient();
if (process.env.NODE_ENV !== "production") globalForPrisma.db = db;

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules