Describe the bug
Profile image uploads fail in Kan when using the official Docker image (ghcr.io/kanbn/kan:latest and v0.4.1) with Docker volumes or host-mounted directories. Even when directories are writable by the container’s root user, Kan reports:

Error uploading profile image
Please try again later, or contact customer support.

Testing inside the container shows /data is not writable by the internal nextjs:nogroup process, although /tmp is writable. This prevents uploads from succeeding.

To Reproduce
Steps to reproduce the behavior:
1. Deploy Kan using Docker (latest or v0.4.1) with a writable host path or Docker volume mounted to /data and /storage.
2. Start the kan-web container.
3. Attempt to upload a profile image through the web UI.
4. See the error message: “Error uploading profile image. Please try again later, or contact customer support.”

Expected behavior
The profile image should upload successfully to /storage or /data inside the container.