Front end React developer to build a questionnaire and scoring tool for Squarespace embed

I need a client side React questionnaire with 100 items across ten pages, with progress and autosave to localStorage, and in-browser scoring. The app reads items, mappings, and norms from JSON, calculates absolute scores and percentiles, and shows results as bar charts with CSV export. Add a small API to store all answers and computed outcomes on my VPS with no PII collected and IPs not retained. Provide a simple PostgreSQL schema and migrations. Deliver a clean static front end on a subdomain and embed it on my Squarespace site via iframe with auto resize. Include source code, build artefacts, API code, and a short README for deploy and embed.

Design the app so instruments load by route and read their own JSON, keep scoring in a separate module for each instrument, store the instrument and version on every record, and document how to add a new instrument without touching shared code.