fix: Address review feedback on OpenAI provider

- Remove accidentally committed package-lock.json (37k lines) and add it
  to .gitignore -- this is a Yarn 4.5.1 workspace project
- Log a warning when AI_EXTRA_BODY custom fetch cannot parse the request
  body as JSON, instead of silently forwarding it unmodified

Author: vinzee

.gitignore

@@ -51,6 +51,7 @@ packages/app/next-env.d.ts
 
 # optional npm cache directory
 **/.npm
+package-lock.json
 
 # dependency directories
 **/node_modules