fix: resolve CLI backend URL and Vercel deployment issues

- Replace non-existent levelcode.ai domain with levelcode.vercel.app
  in env defaults, schema, and error handling fallback URL
- Add @opentelemetry/api to serverExternalPackages to fix ENOENT
  during Vercel output tracing

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: yethikrishna

cli/src/utils/error-handling.ts

@@ -2,7 +2,7 @@ import { env } from '@levelcode/common/env'
 
 import type { ChatMessage } from '../types/chat'
 
-const defaultAppUrl = env.NEXT_PUBLIC_LEVELCODE_APP_URL || 'https://levelcode.com'
+const defaultAppUrl = env.NEXT_PUBLIC_LEVELCODE_APP_URL || 'https://levelcode.vercel.app'
 
 // Normalize unknown errors to a user-facing string.
 const extractErrorMessage = (error: unknown, fallback: string): string => {

common/src/env-schema.ts

@@ -4,7 +4,7 @@ export const CLIENT_ENV_PREFIX = 'NEXT_PUBLIC_'
 
 export const clientEnvSchema = z.object({
   NEXT_PUBLIC_CB_ENVIRONMENT: z.enum(['dev', 'test', 'prod']).default('prod'),
-  NEXT_PUBLIC_LEVELCODE_APP_URL: z.string().default(''),
+  NEXT_PUBLIC_LEVELCODE_APP_URL: z.string().default('https://levelcode.vercel.app'),
   NEXT_PUBLIC_SUPPORT_EMAIL: z.string().default('support@levelcode.ai'),
   NEXT_PUBLIC_POSTHOG_API_KEY: z.string().default(''),
   NEXT_PUBLIC_POSTHOG_HOST_URL: z.string().default('https://app.posthog.com'),

common/src/env.ts

@@ -5,7 +5,7 @@ const parsedEnv = clientEnvSchema.safeParse(clientProcessEnv)
 // Provide fallback values for CLI usage where env vars may not be set
 const fallbackEnv = {
   NEXT_PUBLIC_CB_ENVIRONMENT: 'prod' as const,
-  NEXT_PUBLIC_LEVELCODE_APP_URL: '',
+  NEXT_PUBLIC_LEVELCODE_APP_URL: 'https://levelcode.vercel.app',
   NEXT_PUBLIC_SUPPORT_EMAIL: 'support@levelcode.ai',
   NEXT_PUBLIC_POSTHOG_API_KEY: '',
   NEXT_PUBLIC_POSTHOG_HOST_URL: 'https://app.posthog.com',

web/next.config.mjs

@@ -23,6 +23,9 @@ const nextConfig = {
   },
   allowedDevOrigins: DEV_ALLOWED_ORIGINS,
 
+  // Externalize packages that cause ENOENT during Vercel output tracing
+  serverExternalPackages: ['@opentelemetry/api'],
+
   // Enable experimental features for better SSG performance
   experimental: {
     optimizePackageImports: ['@/components/ui'],