Error building Docker image

Building the Docker image is failing with the following errors:

```
W: GPG error: http://deb.debian.org/debian bookworm InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0E98404D386FA1D9 NO_PUBKEY 6ED0E7B82643E131 NO_PUBKEY F8D2585B8783D481
E: The repository 'http://deb.debian.org/debian bookworm InRelease' is not signed.
E: The repository 'http://deb.debian.org/debian-security bookworm-security InRelease' is not signed.
E: Problem executing scripts APT::Update::Post-Invoke 'rm -f /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin || true'
E: Sub-process returned an error code
The command '/bin/sh -c apt update && apt install age # && apt clean' returned a non-zero code: 100
```

Locate the Docker build entry point containing `apt update && apt install age`, then reproduce the failure and inspect the Debian repository and GPG-key setup involved. Done means the Docker image builds successfully without the reported APT errors.

Written by the indexing model from the issue text.