Sveltekit SaaS Chatbot App Development

I'm looking to build a robust Sveltekit-based SaaS chatbot application. The system should support multiple teams and users, along with subscription management. A critical aspect of this project is the incorporation of AI agents.

Key requirements for the project include:

- A UI for creating and managing AI agents, akin to custom GPTs. The agents should have the capability of handling document uploads with RAG, using LangChain or a similar tool.
- The AI agents should be able to manage:
- Document upload and retrieval
- Customizable instructions
- Custom model settings

- A chat interface that features:
- Real-time messaging
- Message attachments
- Markdown rendering

Technologies I'd prefer we use:
- SvelteKit
- Tailwind
- shadcn UI
- some sort of starter repo like https://saasstarter.work/ or something similar to jumpstart the project

I'm particularly interested in using LangChain for the AI agents. Given this, your expertise and experience with this tool will be highly beneficial.

Ideal Skills and Experience:
- Proficiency in Sveltekit
- Experience in building SaaS applications
- Familiarity with LangChain
- UI/UX design skills
- Understanding of chatbot development
- Knowledge of subscription-based model implementation
- Ability to setup production hosting for the project

Please provide examples of similar projects you have completed in the past.