Mitigate CVE-2025-55182 (React2Shell)

[c0ball]

I noticed that the currently available Docker image in the GitHub registry uses Next.js version 15.5.4, which is affected by the critical React2Shell vulnerability (CVE-2025-55182, CVSS 10.0).

Since I'm not sure to what extent this affects Cap, I wanted to ask if someone could take a look at this, update the Next.js version to 15.5.9 and publish new Docker images.

Thank you in advance for looking into this!

[linear]

CAP-575