Custom Shopify App Build -- 3

Build a Shopify custom product options app (like Hulk/Infinite Options) with these features:

- Shopify’s 100-variant limit → store options in Postgres DB, attach via line item properties.
- Bulk editing with free open-source spreadsheet (JSpreadsheet CE or Handsontable CE).
- Full variant combination generator: supports price, SKU, inventory per combination.
- Template system: apply to single/multiple products or collections; supports groups of variations.
- Conditional logic (show/hide options based on selections).
- Dynamic price updates on product page.

UI controls supported: text swatch, image swatch, color swatch, checkboxes, toggle, dropdown, textbox, textarea, file upload, date picker, custom HTML, Shopify Liquid injection.
Each option has: priority number (for display order), required/optional, tooltip.
Options can be grouped; multiple groups can be applied to collections/products.

Deliverables:
1. **Backend** (Node/Express + Postgres): endpoints for templates, groups, options, spreadsheet sync, variant generation.
2. **Frontend Widget** (JS/React): renders controls, applies conditional logic, updates price, sends line item properties.
3. **Admin Dashboard** (React + Shopify Polaris): template builder, option groups, spreadsheet editor, bulk assignment to products/collections.
4. **Deployment**: Dockerfile + ready for Render/Railway/Heroku.

Build step by step: schema → backend → spreadsheet integration → frontend widget → admin dashboard.