N8N WhatsApp AI Sales Automation

I need a robust AI-driven sales agent built with n8n that can close sales of physical products entirely through WhatsApp.
Here’s what I expect:

• Core flow: The agent greets prospects, qualifies them, recommends the right product from our catalogue of products, answers objections, collects shipping details and triggers payment via Stripe—all inside a single WhatsApp conversation.
• Tech stack: n8n orchestration, WhatsApp Business Cloud API, PHP endpoints where needed, Stripe checkout links or payment intents, plus any third-party tools you feel will amplify the experience. Clean REST or webhook integrations are crucial.
• Intelligence layer: Apply a lightweight machine-learning or agent-based model so the bot learns from previous chats, improves its upsell timing, and adapts product suggestions. I’m open to your preferred frameworks as long as training data stays secure.
• API connectivity: The flow must pull stock levels, shipping rates and order status from our existing systems via documented APIs, then write back confirmed orders in real time.
• Handover: Clear n8n workflow diagrams, commented code, environment variables, and a short Loom/YouTube demo showing the conversation in action.

Please send a detailed project proposal outlining your strategy, tools, and timeline.