Coreprep monorepo

Overview
- Product: exam-prep for Morocco.
- Phase 1: Concours QCM fully working.
- BAC (exercise-based) is planned next; data model must allow it.

Structure
- apps/web: Next.js + TypeScript web app.
- packages/core: adaptive engine placeholder.
- packages/content: import/seed tools placeholder.
- supabase/migrations: database migrations.
- supabase/seed: seed data scripts.

Local setup
1) Install pnpm (https://pnpm.io/installation).
2) Install dependencies:
   pnpm install
3) Create environment file (macOS/Linux):
   cp .env.example .env

   Windows PowerShell:
   Copy-Item .env.example .env

   For the web app env file:
   Copy-Item apps/web/.env.example apps/web/.env.local
4) Run the web app:
   pnpm dev

Auth flow check
- Sign up: http://localhost:3000/auth/sign-up
- Sign in: http://localhost:3000/auth/sign-in
- Protected app page: http://localhost:3000/app

Notes
- No Supabase keys are committed. Use .env and apps/web/.env.local for local values.