Full-Stack Developer to Build MVP for B2B SaaS

I'm building a B2B SaaS product for a service-industry vertical involving multi-party coordination — clients, vendors, and internal team members working across complex, multi-stage projects. Think CRM + project management + budget tracking, purpose-built for a workflow that generic tools don't handle well. What already exists This isn't a from-scratch build: A working interactive front-end demo (React + Vite + Tailwind) covering core modules: dashboard, CRM, project workspace, vendor/resource management, budget tracking, tasks, timeline, AI assistant, and templates — currently running on mock data A complete relational database schema (Postgres via Supabase) already designed and migrated, covering multi-tenant organizations, users, clients, vendors, tasks, timelines, budgets, and activity logs Row-Level Security (RLS) policies written and verified for multi-tenant data isolation A secure signup/auth function already built and verified A separate development branch, isolated from the protected demo branch What I need built Convert the existing demo into a live product with real accounts and real data, phase by phase: Real user authentication (wired to existing auth function) Core CRUD for clients/customers Core CRUD for the main project/workspace object Vendor/resource management + budget module Live payments integration (Stripe or similar) Tasks + timeline AI assistant — live LLM API integration against real user data Documents module Live dashboard (replacing mock data) Templates library I want each phase scoped, quoted, and approved separately rather than one large handoff. Requirements Proven experience with Supabase — auth, RLS, edge functions, Postgres (please point to a project with multi-tenant RLS) Strong React + Vite + Tailwind Experience integrating a third-party LLM API (Claude, OpenAI, etc.) into a production feature Experience integrating Stripe or similar for live payments Comfortable implementing against an existing schema rather than redesigning from scratch Comfortable with milestone-based, iterative delivery with review at each phase Clear communicator — I'm non-technical and want a collaborator who explains decisions, not just ships code Full IP transfer on completion of each milestone Nice to Have Experience with multi-tenant B2B SaaS products Experience with booking/marketplace-style, multi-party coordination products Deliverables per Phase Working, deployed feature on the dev branch Brief written explanation of implementation decisions Confirmation RLS was tested/verified for new functionality