fix: prevent Prisma connection pool exhaustion in production

Cache PrismaClient globally in ALL environments (was only cached in dev).
Without this, production could create multiple PrismaClient instances,
each with its own connection pool, exhausting the database connections.

v1.71.2

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "my-weekly-todo-list",
-  "version": "1.71.1",
+  "version": "1.71.2",
   "description": "A web-based weekly task management application that organizes to-dos and calendar events in a single, intuitive weekly view",
   "main": "index.js",
   "scripts": {

src/lib/prisma.ts

@@ -2,6 +2,15 @@ import { PrismaClient } from '@prisma/client';
 
 const globalForPrisma = global as unknown as { prisma: PrismaClient };
 
-export const prisma = globalForPrisma.prisma || new PrismaClient();
+export const prisma =
+  globalForPrisma.prisma ||
+  new PrismaClient({
+    datasources: {
+      db: {
+        url: process.env.DATABASE_URL,
+      },
+    },
+  });
 
-if (process.env.NODE_ENV !== 'production') globalForPrisma.prisma = prisma;
+// Cache the client globally in ALL environments to prevent connection pool exhaustion
+globalForPrisma.prisma = prisma;