Senior Next.js + Supabase dev to help extend our in-house ERP

We're Redstone Manufacturing. We source custom metal parts for US companies that don't have the experience or capacity to source overseas themselves. CNC machining, sheet metal, casting, injection molding. We built our own ERP instead of buying one. It's in daily use by about 7 people. It tracks purchase orders, shipments, lots, inspection schedules, and AP against QuickBooks, which stays our system of record. It was built almost entirely with Claude Code. That's gone better than we expected and we're not looking to throw it out. We want someone who can work on it properly. What it is Next.js 16 App Router, TypeScript, Tailwind 4, on Vercel Supabase for Postgres and auth, 27 tables, two dozen migrations 14 pages, server-rendered, every one saves as you edit An MCP endpoint so our team can query the ERP from Claude xlsx exports, QuickBooks imports, and an unattended email-to-import path What we need help with - Fixing bugs and handling support requests as they come up. - Building new features as we extend the data model. - Working from a fast built prototype toward more production grade code without a rewrite from scratch. - Comfortable reading and improving code you didn't write, including code that was built quickly under time pressure. Who this suits You've shipped App Router work recently. Next 16, not Next 13. You know Supabase well enough to have opinions about RLS. You're fine reading a codebase you didn't write, and one an AI wrote much of. You don't need manufacturing experience. You do need to ask about the business logic before you change it. A lot of it looks wrong until you know why it's there. How it works Part time to start, 10 to 15 hours a week, hourly. US Central time. Some overlap with our day matters because questions come up. To apply, tell me about a Next.js app or ERP system you took over from someone else and what you changed first.