feat: force port 3000 to make Next.js abort startup on multiple instances clashing on same port

env/client.ts

@@ -2,7 +2,11 @@ import { createEnv } from "@t3-oss/env-nextjs"
 import { z } from "zod"
 
 export const env = createEnv({
-  client: { NEXT_PUBLIC_PORT: z.string().optional() },
+  client: {
+    NEXT_PUBLIC_PORT: z.string().default("3000"),
+  },
   emptyStringAsUndefined: true,
-  runtimeEnv: { NEXT_PUBLIC_PORT: process.env.PORT },
+  runtimeEnv: {
+    NEXT_PUBLIC_PORT: process.env.NEXT_PUBLIC_PORT,
+  },
 })