setup-stacklisted

Bootstrap the canonical SaaS Studio stack from scratch: Next.js App Router, TypeScript, Tailwind CSS, shadcn/ui, Supabase client, and Stripe SDK. Non-autonomous: every command and every generated file is shown to the user for approval before execution — nothing runs without sign-off. ## Phases 1. **Confirm prerequisites** — check that Node.js >= 18, `npm`/`pnpm`, and the Supabase CLI are available. Report what is found. If the project directory already contains a `package.json`, warn the user and ask whether to continue or abort. 2. **Present the scaffold plan** — show the exact sequence of commands that will be run: `npx create-next-app@latest` with `--typescript --tailwind --app --eslint`, followed by `npx shadcn@latest init`, then `npm install @supabase/ssr @supabase/supabase-js stripe @stripe/stripe-js`. List the commands verbatim. Do not run until the user approves. 3. **Run scaffold** — execute the approved commands with `Bash`. Stream output; stop and surface any error immediately rather than continuing past a failure. 4. **Write `.env.example`** — create `.env.example` at the project root with all required keys: `NEXT_PUBLIC_SUPABASE_URL`, `NEXT_PUBLIC_SUPABASE_ANON_KEY`, `SUPABASE_SERVICE_ROLE_KEY`, `STRIPE_SECRET_KEY`, `STRIPE_WEBHOOK_SECRET`, `NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY`, `NEXT_PUBLIC_APP_URL`. Values must be placeholders (e.g., `your-supabase-url`), never real secrets. Show the file contents for approval before writing. 5. **Verify the scaffold** — run `t