fix: explicit prisma client installation and move prisma to devDependencies

src/lib/prisma.ts

@@ -0,0 +1,23 @@
+import { PrismaClient } from "../generated/prisma";
+import { PrismaPg } from "@prisma/adapter-pg";
+import pg from "pg";
+
+const globalForPrisma = global as unknown as { prisma: PrismaClient };
+
+const connectionString = process.env.DATABASE_URL;
+
+if (!connectionString) {
+  throw new Error("DATABASE_URL is not set");
+}
+
+const pool = new pg.Pool({ connectionString });
+const adapter = new PrismaPg(pool);
+
+export const prisma =
+  globalForPrisma.prisma ||
+  new PrismaClient({
+    adapter,
+    log: ["query"],
+  });
+
+if (process.env.NODE_ENV !== "production") globalForPrisma.prisma = prisma;