feat(security): HttpOnly cookie sessions, token revocation, and RBAC

- Add User.role (enum Role/ADMIN) and User.tokenVersion with migration
- Login now issues short-lived access token (30m default) + 7d refresh
  token, both embedding tokenVersion and a typ discriminator
- Tokens delivered via HttpOnly SameSite cookies (ir_at, ir_rt scoped
  to /auth); refresh token never leaves the cookie
- New endpoints: POST /auth/refresh (rotation), GET /auth/me,
  POST /auth/logout (bumps tokenVersion, revoking all tokens)
- JWT strategy accepts bearer or cookie, rejects refresh tokens, and
  verifies tokenVersion + user existence on every request
- Global RolesGuard: authenticated routes require ADMIN unless widened
  via @Roles(...)
- Admin SPA: session fully cookie-based, no token in localStorage;
  router guard restores session via /auth/me; axios auto-refreshes once
  on 401; stale localStorage keys cleaned up

apps/api/prisma/migrations/20260824000000_add_user_role_token_version/migration.sql

@@ -0,0 +1,8 @@
+-- Create enum for user roles
+CREATE TYPE "Role" AS ENUM ('ADMIN');
+
+-- Add role column, existing users become ADMIN
+ALTER TABLE "users" ADD COLUMN "role" "Role" NOT NULL DEFAULT 'ADMIN';
+
+-- Token version for JWT revocation (logout bumps it)
+ALTER TABLE "users" ADD COLUMN "token_version" INTEGER NOT NULL DEFAULT 0;