Optional Sign in with ChatGPT provider for native AI features

I would like to use my existing ChatGPT/Codex subscription directly with Paperless-ngx's built-in AI features, without configuring a separately billed API account or another document-processing application. The existing title, tag, correspondent, document type and date suggestions, document chat, and "Apply AI suggestions" workflows are the integration I am looking for. Local models have not produced satisfactory classification results for my documents. Would the maintainers be interested in supporting "Sign in with ChatGPT" as an optional AI provider? OpenAI now documents a sign-in flow for open-source applications that can use eligible users' ChatGPT plans: Ideally, users could connect their account in Paperless settings and use the existing native AI features within their plan's available limits. Cloud processing would be explicitly opt-in, with a clear explanation that document content is sent to OpenAI. Existing local providers would remain…