fix compute instance show: display multiple ssh keys

[aureliar8]

Description

The cli (during compute instance show) was still using the deprecated sshKey fieldas the source of truth while nowadays it's sshKeys (plural) that needs to be used as an instance can have multiple ssh keys

Creation was already working fine

Checklist

(For exoscale contributors)

• Changelog updated (under Unreleased block, and add the Pull Request #number for each bit you add to the CHANGELOG.md)
• Testing

Testing

Before

❯ exo c i create test-with-ssh-keys --ssh-key k1 --ssh-key k2 --ssh-key k3
 ✔ Creating instance "test-with-ssh-keys"... 24s
┼─────────────────────────────────────────┼──────────────────────────────────────┼
│            COMPUTE INSTANCE             │                                      │
┼─────────────────────────────────────────┼──────────────────────────────────────┼
│ ID                                      │ ad37e967-765d-4071-b99b-3c256baf5bdd │
│ Name                                    │ test-with-ssh-keys                   │
│ Creation Date                           │ 2026-08-19 07:50:20 +0000 UTC        │
│ Instance Type                           │ standard.medium                      │
│ Template                                │ Linux Ubuntu 24.04 LTS 64-bit        │
│ Zone                                    │ ch-gva-2                             │
│ Anti-Affinity Groups                    │ n/a                                  │
│ Deploy Target                           │ -                                    │
│ Security Groups                         │ default                              │
│ Private Instance                        │ No                                   │
│ Private Networks                        │ n/a                                  │
│ Elastic IPs                             │ n/a                                  │
│ Public IP                               │ inet4                                │
│ IP Address                              │ 151.145.196.141                      │
│ IPv6 Address                            │ -                                    │
│ SSH Key                                 │ k1                                   │
│ Disk Size                               │ 50 GiB                               │
│ State                                   │ running                              │
│ Labels                                  │ n/a                                  │
│ Secure Boot                             │ false                                │
│ Tpm                                     │ false                                │
│ Reverse DNS                             │                                      │
│ Application-Consistent Snapshot enabled │ false                                │
┼─────────────────────────────────────────┼──────────────────────────────────────┼

after

❯ go run . c i show test-with-ssh-keys
┼─────────────────────────────────────────┼──────────────────────────────────────┼
│            COMPUTE INSTANCE             │                                      │
┼─────────────────────────────────────────┼──────────────────────────────────────┼
│ ID                                      │ ad37e967-765d-4071-b99b-3c256baf5bdd │
│ Name                                    │ test-with-ssh-keys                   │
│ Creation Date                           │ 2026-08-19 07:50:20 +0000 UTC        │
│ Instance Type                           │ standard.medium                      │
│ Template                                │ Linux Ubuntu 24.04 LTS 64-bit        │
│ Zone                                    │ ch-gva-2                             │
│ Anti-Affinity Groups                    │ n/a                                  │
│ Deploy Target                           │ -                                    │
│ Security Groups                         │ default                              │
│ Private Instance                        │ No                                   │
│ Private Networks                        │ n/a                                  │
│ Elastic IPs                             │ n/a                                  │
│ Public IP                               │ inet4                                │
│ IP Address                              │ 151.145.196.141                      │
│ IPv6 Address                            │ -                                    │
│ SSH Keys                                │ k1                                   │
│                                         │ k2                                   │
│                                         │ k3                                   │
│ Disk Size                               │ 50 GiB                               │
│ State                                   │ running                              │
│ Labels                                  │ n/a                                  │
│ Secure Boot                             │ false                                │
│ Tpm                                     │ false                                │
│ Reverse DNS                             │                                      │
│ Application-Consistent Snapshot enabled │ false                                │
┼─────────────────────────────────────────┼──────────────────────────────────────┼

[quentinalbertone]

suggestion: you can directly allocate InstanceShowOutput.SSHKeys with the size of instance.SSHKeys

[aureliar8]

I did that for consistency with over zero-initialized arrays in the rest of the codebase