Add --output=json to ls subcommands

[miekg]

This PR add --output=json to only the command that have an ls.go. The json keys are copied from docker and are camelCase, json struct tags are added where needed.

It does not change any of the inspect commands, that should be another issue. It also doesn't do any prework for future output formats, it only handles json.

Fixes: #338 #337

[miekg]

you can't (easily) change the struct tags of generated protobufs ... these are now all in snake case.
See golang/protobuf#52

[miekg]

example for machine:

% uc machine ls
NAME           STATE   ADDRESS         PUBLIC IP       WIREGUARD ENDPOINTS   MACHINE ID
machine-781l   Up      10.210.0.1/24   131.174.88.77   131.174.88.77:51820   c22073beee04bf9b1861e53c21023d2d
machine-9q7y   Up      10.210.1.1/24   131.174.88.78   131.174.88.78:51820   212fd73438b53ebfb7dd531da4c6ed41

and % uc machine ls --output=json

{
  "Machines": [
    {
      "machine": {
        "id": "c22073beee04bf9b1861e53c21023d2d",
        "name": "machine-781l",
        "network": {
          "subnet": {
            "ip": "10.210.0.0",
            "bits": 24
          },
          "management_ip": "fdcc:fb07:d7f4:2509:ae43:19af:90b:1147",
          "endpoints": [
            "131.174.88.77:51820"
          ],
          "public_key": "+wfX9CUJrkMZrwkLEUcyitNurEAcuki3VqTyidcsVGw="
        },
        "public_ip": "131.174.88.77"
      },
      "state": 1
    },
    {
      "machine": {
        "id": "212fd73438b53ebfb7dd531da4c6ed41",
        "name": "machine-9q7y",
        "network": {
          "subnet": {
            "ip": "10.210.1.0",
            "bits": 24
          },
          "management_ip": "fdcc:7911:76ad:b00c:9f0e:5ed4:9b81:ee70",
          "endpoints": [
            "131.174.88.78:51820"
          ],
          "public_key": "eRF2rbAMnw5e1JuB7nCwxYMaH1lsoMMwuS63c+Dm9lI="
        },
        "public_ip": "131.174.88.78"
      },
      "state": 1
    }
  ]
}

[miekg]

as wg only has show command that one didn't get a --output=json

[miekg]

and volume for instance - different keys:

% uc volume ls --output=json                                                                                                   ~miekg/uncloud/cmd/uncloud miek/26/apr29wo/jsonflag
{
  "Volumes": [
    {
      "MachineID": "212fd73438b53ebfb7dd531da4c6ed41",
      "MachineName": "machine-9q7y",
      "Volume": {
        "CreatedAt": "2026-04-24T11:23:14Z",
        "Driver": "local",
        "Labels": {
          "nl.ru.science.backup": "kopia",
          "uncloud.managed": ""
        },
        "Mountpoint": "/var/lib/docker/volumes/atomdns_data/_data",
        "Name": "atomdns_data",
        "Options": null,
        "Scope": "local"
      }
    },
    {
      "MachineID": "212fd73438b53ebfb7dd531da4c6ed41",
      "MachineName": "machine-9q7y",
      "Volume": {
        "CreatedAt": "2026-04-24T11:10:25Z",
        "Driver": "local",
        "Labels": {
          "uncloud.managed": ""
        },
        "Mountpoint": "/var/lib/docker/volumes/db_data/_data",
        "Name": "db_data",
        "Options": null,
        "Scope": "local"
      }
    }
  ]
}

dont know how much this actually matter in json actualy...

Well is does matter. Adding a post-process json function is very easy, so we could rewrite all the keys into a way to makes it all more consistent