fix: pin @swc/helpers explicitly so npm ci works on npm 10 (Alpine)

The Docker build on the VPS failed because:
  npm error Missing: @swc/helpers@0.5.21 from lock file

Cause: Next.js 16.1.6 declares @swc/helpers both as a direct dep at
0.5.15 AND as a peer dep ">=0.5.17". npm 11 (my local) accepts the
0.5.15 install and considers the peer satisfied. npm 10.9.7 (the
Alpine container in the VPS) is stricter — it tries to resolve the
peer to its own version and demands 0.5.21, which our lock file
didn't have.

Fix:
- Add @swc/helpers ^0.5.17 as a direct dependency so both npm 10 and
  npm 11 pick the same up-to-date version (resolved to 0.5.21).
- Regenerate package-lock.json from a clean install so it matches.

`npm ci` now succeeds in the docker-compose build.

package.json

@@ -15,6 +15,7 @@
     "@prisma/client": "^7.5.0",
     "@react-three/drei": "^10.7.7",
     "@react-three/fiber": "^9.5.0",
+    "@swc/helpers": "^0.5.17",
     "@types/nodemailer": "^7.0.11",
     "ai": "^6.0.116",
     "bcryptjs": "^3.0.3",