[Bug]: `--dns` and `--no-dns` can be supplied together

[realrajaryan]

I have done the following

• I have searched the existing issues
• If possible, I've reproduced the issue using the 'main' branch of this project

Steps to reproduce

Run or create a container with both explicit DNS configuration and DNS disabled:

$ container run --rm --dns 1.1.1.1 --no-dns alpine:latest true
[0/6] [0s]
[1/6] Fetching image [0s]
[2/6] Unpacking image [0s]
[3/6] Fetching kernel [0s]
[4/6] Fetching init image [0s]
[5/6] Unpacking init image [0s]
[6/6] Starting container [0s]
[6/6] Starting container [0s]

$ echo $?
0

$ container create --name issue-dns-conflict --dns 1.1.1.1 --no-dns alpine:latest true
issue-dns-conflict

$ echo $?
0

$ container inspect issue-dns-conflict
[{"configuration":{"publishedSockets":[],"resources":{"memoryInBytes":1073741824,"cpus":4},"image":{"reference":"docker.io\/library\/alpine:latest","descriptor":{"size":9218,"mediaType":"application\/vnd.oci.image.index.v1+json","digest":"sha256:5b10f432ef3da1b8d4c7eb6c487f2f5a8f096bc91145e68878dd4a5019afde11"}},"mounts":[],"publishedPorts":[],"id":"issue-dns-conflict","labels":{},"readOnly":false,"capAdd":[],"runtimeHandler":"container-runtime-linux","initProcess":{"supplementalGroups":[],"terminal":false,"rlimits":[],"arguments":[],"environment":["PATH=\/usr\/local\/sbin:\/usr\/local\/bin:\/usr\/sbin:\/usr\/bin:\/sbin:\/bin"],"executable":"true","workingDirectory":"\/","user":{"id":{"gid":0,"uid":0}}},"ssh":false,"sysctls":{},"capDrop":[],"networks":[{"options":{"hostname":"issue-dns-conflict","mtu":1280},"network":"default"}],"platform":{"os":"linux","architecture":"arm64"},"virtualization":false,"useInit":false,"rosetta":false},"networks":[],"status":"stopped"}]

Problem description

--dns and --no-dns are contradictory. The CLI accepts both and silently lets --no-dns win. It should reject the combination, or clearly document and report precedence.

Environment

- OS: macOS 26.4.1 (25E253)
- Xcode: Xcode 26.4.1 (17E202)
- Container: container CLI 0.12.3 (build: release, commit: f989901)

Code of Conduct

• I agree to follow this project's Code of Conduct