chore: harden deps, env validation, admin errors, and redis warnings

Align nodemailer with Auth.js peers, bump patch deps, validate env on deploy builds, add admin error boundary, and warn when Redis is missing in production.

Co-authored-by: Cursor <[email protected]>

.gitea/workflows/deploy.yaml

@@ -292,7 +292,8 @@ jobs:
           pnpm prisma:generate
           pnpm typecheck
           pnpm test
-          export SKIP_ENV_VALIDATION=1
+          # Validate production env (AUTH_SECRET, DATABASE_URL, …) during build.
+          # Do not set SKIP_ENV_VALIDATION here — that flag is for tests/tooling only.
           pnpm build
 
           sudo chown -R www-data:www-data /var/www/atom-nexst/