c5a2fc9105
- safeReturnTo resolves the target against a placeholder origin and rejects backslashes and control characters, so `/\evil.example` and similar payloads can no longer redirect off-site after sign-in. - Add a real unauthenticated /api/health and answer unknown /api/* paths with a JSON 404 instead of the SPA shell. - Limit request bodies: 16 KB for /api/auth/* (read before a session exists), 128 MB for resource create/update and uploads, 10 MB elsewhere. - Run the production image as an unprivileged user and add a Docker HEALTHCHECK against /api/health.