✨ Implement `sshctl key show` command

[AndreLeclercq]

Goal

Display an SSH public key for easy copying to servers/services.

Command

sshctl key show <key-name>

Features

• Display full public key content
• Search in ~/.ssh/.pub by default
• Support full paths
• Clear error if key not found with suggestions

Example Usage

  $ sshctl key show github-personal
  ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGQw... github-personal

Optional Enhancement

• Copy to clipboard