Add --gh-keys so sshd setup can run without prompts (#7086)

* Add --gh-keys so sshd setup can run without prompts

Grabbing keys from GitHub was reachable only through the interactive menu: pick
"Grab key from GitHub", then type the username into a second prompt. So the one
path that needs no secret pasted around was also the one path a script could not
take, and setting a machine up over ssh or from a provisioning run meant falling
back to --key with a key copied by hand.

--gh-keys <username> takes the same path the prompt did. The fetch and authorize
logic is unchanged and now shared, with the prompt reduced to asking for the
username and handing it over.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

* Reject a missing --gh-keys username before setting anything up

The username was only checked for being absent entirely, and only after the
server was installed and the firewall opened. So `--gh-keys=` with an unset
variable behind it configured the machine and then dropped into the interactive
menu, and `--gh-keys --help` took --help as the username and set the server up
on its way to failing the fetch -- a help flag that changes the system.

Check the value where it is parsed, and reject one that is empty or shaped like
an option.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

bin/omarchy-setup-security-sshd

@@ -1,32 +1,62 @@
 #!/bin/bash
 
 # omarchy:summary=Set up the OpenSSH server, open the firewall, and authorize an SSH key
-# omarchy:args=[--key=<public-key>]
-# omarchy:examples=omarchy-setup-security-sshd | omarchy-setup-security-sshd --key="ssh-ed25519 AAAA... user@host"
+# omarchy:args=[--key=<public-key>] [--gh-keys <github-username>]
+# omarchy:examples=omarchy-setup-security-sshd | omarchy-setup-security-sshd --gh-keys dhh | omarchy-setup-security-sshd --key="ssh-ed25519 AAAA... user@host"
 # omarchy:requires-sudo=true
 
 set -e
 
 AUTHORIZED_KEYS="$HOME/.ssh/authorized_keys"
 KEY=""
+GITHUB_USER=""
 
-for arg in "$@"; do
-  case "$arg" in
-  --key=*) KEY="${arg#--key=}" ;;
+# Checked while parsing, before anything is installed or opened: an empty or
+# option-shaped username otherwise falls through to the interactive menu having
+# already changed the machine, and `--gh-keys --help` would take --help as the
+# username and set the server up on its way to failing.
+require_github_user() {
+  if [[ -z $1 || $1 == -* ]]; then
+    echo "omarchy-setup-security-sshd: --gh-keys needs a GitHub username." >&2
+    exit 2
+  fi
+}
+
+while (( $# > 0 )); do
+  case "$1" in
+  --key=*) KEY="${1#--key=}" ;;
+  --gh-keys=*)
+    GITHUB_USER="${1#--gh-keys=}"
+    require_github_user "$GITHUB_USER"
+    ;;
+  --gh-keys)
+    shift
+    GITHUB_USER="${1:-}"
+    require_github_user "$GITHUB_USER"
+    ;;
   -h | --help)
-    echo "Usage: omarchy-setup-security-sshd [--key=<public-key>]"
+    echo "Usage: omarchy-setup-security-sshd [--key=<public-key>] [--gh-keys <github-username>]"
     echo
     echo "Sets up the OpenSSH server, opens the SSH port in the UFW firewall,"
     echo "and authorizes an SSH key (from GitHub, pasted, or passed via --key)."
+    echo
+    echo "Passing --key or --gh-keys skips the prompts, so the command can run"
+    echo "unattended from a script or a fresh machine's first login."
     exit 0
     ;;
   *)
-    echo "omarchy-setup-security-sshd: unknown option '$arg'. Try --help." >&2
+    echo "omarchy-setup-security-sshd: unknown option '$1'. Try --help." >&2
     exit 2
     ;;
   esac
+  shift
 done
 
+if [[ -n $KEY && -n $GITHUB_USER ]]; then
+  echo "omarchy-setup-security-sshd: pass either --key or --gh-keys, not both." >&2
+  exit 2
+fi
+
 setup_sshd() {
   echo "Installing and starting the OpenSSH server..."
   omarchy-pkg-add openssh
@@ -70,13 +100,7 @@ authorize_key() {
 }
 
 authorize_keys_from_github() {
-  local username keys added=0
-
-  username=$(gum input --prompt "GitHub username> " --placeholder "dhh") || exit 1
-  if [[ -z $username ]]; then
-    echo -e "\e[31mNo GitHub username given.\e[0m" >&2
-    exit 1
-  fi
+  local username="$1" keys added=0
 
   echo "Fetching keys from https://github.com/$username.keys..."
   if ! keys=$(curl -fsSL "https://github.com/$username.keys") || [[ -z $keys ]]; then
@@ -95,6 +119,18 @@ authorize_keys_from_github() {
   fi
 }
 
+prompt_for_github_user() {
+  local username
+
+  username=$(gum input --prompt "GitHub username> " --placeholder "dhh") || exit 1
+  if [[ -z $username ]]; then
+    echo -e "\e[31mNo GitHub username given.\e[0m" >&2
+    exit 1
+  fi
+
+  authorize_keys_from_github "$username"
+}
+
 authorize_pasted_key() {
   local key
 
@@ -115,9 +151,11 @@ open_firewall
 echo
 if [[ -n $KEY ]]; then
   authorize_key "$KEY" || exit 1
+elif [[ -n $GITHUB_USER ]]; then
+  authorize_keys_from_github "$GITHUB_USER"
 else
   case $(gum choose "Grab key from GitHub" "Paste key manually" --header "How would you like to add your SSH key?") in
-  "Grab key from GitHub") authorize_keys_from_github ;;
+  "Grab key from GitHub") prompt_for_github_user ;;
   "Paste key manually") authorize_pasted_key ;;
   *) exit 1 ;;
   esac