build: ship pre-built API bundle; images copy output instead of installing

- API: `pnpm build` bundles dist/ into apps/api/.output (esbuild), with
  Linux musl native packages for sharp and argon2 kept alongside
- docker/api.Dockerfile copies that output; no pnpm install on the server
- add dist/migrate.js (prisma migrate deploy equivalent, same
  _prisma_migrations table and lock) so the Prisma CLI is not needed at runtime
- pnpm-workspace: supportedArchitectures for linux/x64/musl
- admin: apps/admin/.env.production sets VITE_SITE_URL for the production build
- drop NPM_REGISTRY / SITE_URL build args from compose and .env.example
- gitignore: anchor node_modules rules so pre-built node_modules are committed
- README: describe the pre-built deploy flow

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>

.env.example

@@ -29,6 +29,3 @@ REVALIDATE_SECRET=change-me-too
 ADMIN_PHONE=09120000000
 ADMIN_PASSWORD=change-me
 ADMIN_NAME=مدیر سایت
-
-# npm registry used while building the images (set a mirror if npmjs.org is slow or blocked)
-NPM_REGISTRY=https://registry.npmjs.org/