v0.5.15: inject cloud-init seed pubkey as admin sshkey at install time

v0.5.14 ships a working install but auto-install harness can't SSH-
validate post-reboot — admin user has no authorized_keys, hardened
sshd rejects all auth. SSH up + listening but no path to log in.

Fix: detect_seed_pubkey() searches /dev/sr* for a NoCloud cidata
volume (label "cidata"), parses ssh_authorized_keys: list from
user-data, returns first key. generate_ks() then embeds as

  sshkey --username=admin "ssh-ed25519 AAAA... user@host"

right after the user= directive. Anaconda creates
/home/admin/.ssh/authorized_keys with right perms (700/600).

Real users: drop a NoCloud seed iso next to install media (or via
USB), pubkey lands automatically. auto-install.sh: existing run-vm.sh
seed logic already builds the cidata iso with host pubkey.

If no seed → directive line empty → anaconda treats as no-op → SSH
validation blocked but install otherwise unaffected.

overlay/usr/local/bin/veilor-installer

@@ -309,6 +309,34 @@ sed_escape() {
     printf '%s' "$1" | sed -e 's/[\\&|/]/\\&/g'
 }
 
+# detect_seed_pubkey — search attached cdroms for a NoCloud cidata seed
+# with an ssh_authorized_keys entry. Returns the first key on stdout, or
+# empty string if none found. Used by both auto-install.sh (cloud-init
+# seed pre-built with host pubkey) and humans (drop a seed iso next to
+# the install media).
+detect_seed_pubkey() {
+    local dev label tmpmnt key=""
+    for dev in /dev/sr0 /dev/sr1 /dev/sr2 /dev/sr3; do
+        [ -b "$dev" ] || continue
+        label=$(blkid -o value -s LABEL "$dev" 2>/dev/null)
+        if [[ $label == "cidata" || $label == "CIDATA" ]]; then
+            tmpmnt=$(mktemp -d)
+            if mount -o ro "$dev" "$tmpmnt" 2>/dev/null; then
+                # NoCloud user-data format:
+                #   ssh_authorized_keys:
+                #     - ssh-ed25519 AAAA... user@host
+                # Extract first ssh-* line, strip leading '- '.
+                key=$(grep -E '^\s*-\s+ssh-' "$tmpmnt/user-data" 2>/dev/null \
+                    | head -1 | sed -e 's/^\s*-\s*//' -e 's/[[:space:]]*$//')
+                umount "$tmpmnt" 2>/dev/null
+            fi
+            rmdir "$tmpmnt" 2>/dev/null
+            [[ -n $key ]] && { printf '%s' "$key"; return 0; }
+        fi
+    done
+    return 1
+}
+
 generate_ks() {
     # Build kickstart for actual disk install.
     # NOTE: passwords go in via --plaintext to avoid storing crypted hash
@@ -345,6 +373,7 @@ firewall --enabled --service=ssh
 
 rootpw --lock
 user --name=admin --groups=wheel --gecos="veilor admin" --password=__ADMIN_PW__ --plaintext
+__SSHKEY_DIRECTIVE__
 
 # Full hardening cmdline (installed system, not live):
 # --location=none: anaconda auto-places bootloader (UEFI grub2-efi or BIOS).
@@ -594,12 +623,25 @@ KSEOF
     # already rejects "$\`&|/\n at input — sed_escape() is defence in
     # depth in case future code paths feed unsanitised values (e.g.
     # locale/hostname from a file, or a relaxed validator).
+    # Detect cloud-init seed pubkey (if attached) → embed as anaconda
+    # `sshkey --username=admin` directive. Adds key to admin's
+    # authorized_keys at install time so SSH validation works first boot.
+    # No seed = empty directive line (anaconda treats blank line as no-op).
+    local seed_pubkey sshkey_directive=""
+    seed_pubkey=$(detect_seed_pubkey 2>/dev/null) || true
+    if [[ -n $seed_pubkey ]]; then
+        echo "[INFO] using cloud-init seed pubkey for admin authorized_keys"
+        # sshkey directive — quote pubkey, no shell meta in pubkeys.
+        sshkey_directive="sshkey --username=admin \"${seed_pubkey}\""
+    fi
+
     sed -i \
         -e "s|__LOCALE__|$(sed_escape "$SEL_LOCALE")|" \
         -e "s|__HOSTNAME__|$(sed_escape "$SEL_HOSTNAME")|" \
         -e "s|__DISK_BASENAME__|$(sed_escape "$disk_basename")|" \
         -e "s|__LUKS_PW__|$(sed_escape "$SEL_LUKS_PW")|" \
         -e "s|__ADMIN_PW__|$(sed_escape "$SEL_ADMIN_PW")|" \
+        -e "s|__SSHKEY_DIRECTIVE__|$(sed_escape "$sshkey_directive")|" \
         "$out"
     echo "[INFO] generated kickstart at $out"
     return 0