Can I vibe code CandyRack?

1. System Architecture & Data Model:
Build a custom Shopify app extension using Remix and Prisma. Store upsell rules using native Shopify Product Metafields under namespace 'custom.upsell_products' (type list.product_reference). Define a Prisma schema for tracking: 'UpsellEvent' (id, shop_domain, trigger_product_id, offered_product_id, event_type: 'VIEW'|'ADD'|'CLOSE', timestamp).

2. Core Functionality:
- Storefront Script: Create a Theme App Extension script. Intercept standard AJAX cart additions by listening to fetch/XMLHttpRequest or binding to form[action='/cart/add'].
- Trigger Logic: On add-to-cart, pause default cart redirect or drawer opening. Read product metafield 'custom.upsell_products'. If empty, fall back to fetching Shopify's native recommendation endpoint ('/recommendations/products.json?product_id={id}&limit=3').
- Modal Overlay: Render a responsive CSS grid modal showing up to 3 recommended products with variant dropdowns, pricing, and an 'Add to Cart' button.
- Cart Update: When a user clicks 'Add to Cart' inside the modal, send an AJAX request to '/cart/add.js' with the selected variant ID, then proceed to the cart drawer or checkout.
- Tracking: Send an asynchronous payload to a serverless API endpoint on modal render, item add, and modal dismiss events.

3. Failure Modes & Edge Cases:
- Inventory Check: Filter out out-of-stock variants before displaying products in the modal.
- Performance Fallback: Set a 350ms network timeout on recommendation fetches. If the API times out, bypass the popup and allow standard cart addition.
- Duplicate Submissions: Disable modal action buttons immediately upon click to prevent multi-add race conditions.

4. Out of Scope:
- Post-purchase checkout extensions (limit scope to pre-purchase / cart modal).
- Multi-armed bandit dynamic pricing algorithms.
- Automated A/B test split routing.

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