cluster0: auth-email bearer + shorten verify URLs in outbound mail

ShortLinksRepository::shortenForOutbound; ensure-auth-email-bearer.sh;
verify-mail-lab sends shortened s.f0xx.org link in verify email body.

Co-authored-by: Cursor <cursoragent@cursor.com>

sim/cluster0/scripts/compose-lab-backend.sh

@@ -122,6 +122,8 @@ if [ -n "$_MSMTP_PASS" ]; then
   MAIL_FROM="${MAIL_FROM:-Android Cast <bestcastr@gmail.com>}"
 fi
 unset _MSMTP_PASS
+AUTH_BEARER_ID="$(read_secret URL_SHORTENER_AUTH_BEARER_ID 2>/dev/null || true)"
+[ -n "$AUTH_BEARER_ID" ] || AUTH_BEARER_ID="${URL_SHORTENER_AUTH_BEARER_ID:-0}"
 mkdir -p "${COMPOSED}/config"
 log "write composed config.php base_path=${ISSUES_BASE}"
 cat > "${COMPOSED}/config/config.php" <<PHP
@@ -174,6 +176,7 @@ return [
     'url_shortener' => [
         'enabled' => true,
         'public_base' => '${SHORT_LINKS_PUBLIC_BASE}',
+        'auth_bearer_id' => ${AUTH_BEARER_ID:-0},
         'db' => [
             'mysql' => [
                 'host' => '${DB_HOST}',