fix: grep -A is not portable, breaks ARI on Solaris

Solaris /usr/bin/grep has no -A ("illegal option -- A"), so _getAKI
printed an error to stderr on every cron renewal and returned empty.
The empty AKI silently corrupts the RFC 9773 ARI certID, so ARI is
never available and renewal falls back to the fixed schedule.

Split the pipeline into a testable stdin filter _extractAKI and select
the value line with a portable sed range instead.

Same fix for the two hooks that still used grep -A: dns_world4you.sh
(also replaces the GNU-only "\s" in the same expression) and
deploy/keyhelp.sh (the -A 2 window could truncate the div range that
follows it, so it is just dropped).

https://github.com/acmesh-official/acme.sh/issues/7159

dnsapi/dns_world4you.sh

@@ -61,7 +61,7 @@ dns_world4you_add() {
     if _contains "$res" "successfully"; then
       return 0
     else
-      msg=$(echo "$res" | grep -A 20 'alert-notification' | grep 'class="weak-title">[^<]' | sed 's/<[^>]*>//g;s/^\s*//g')
+      msg=$(_w4y_alert_msg "$res")
       if [ "$msg" = '' ]; then
         _err "Unable to add record: Unknown error"
         echo "$ret" >'error-01.html'
@@ -125,7 +125,7 @@ dns_world4you_rm() {
     if _contains "$res" "successfully"; then
       return 0
     else
-      msg=$(echo "$res" | grep -A 20 'alert-notification' | grep 'class="weak-title">[^<]' | sed 's/<[^>]*>//g;s/^\s*//g')
+      msg=$(_w4y_alert_msg "$res")
       if [ "$msg" = '' ]; then
         _err "Unable to remove record: Unknown error"
         echo "$ret" >'error-01.html'
@@ -145,6 +145,17 @@ dns_world4you_rm() {
 
 ################ Private functions ################
 
+# Usage: _w4y_alert_msg <html>
+# Extracts the error text out of the alert box of a DNS page.
+# "grep -A" is not portable (Solaris /usr/bin/grep: "illegal option -- A"),
+# so select from the alert to EOF and keep the same number of lines.
+# "\s" is a GNU sed extension, use an explicit space/tab bracket instead.
+_w4y_alert_msg() {
+  _w4y_tab=$(printf '\t')
+  echo "$1" | sed -n '/alert-notification/,$p' | _head_n 21 |
+    grep 'class="weak-title">[^<]' | sed "s/<[^>]*>//g;s/^[ $_w4y_tab]*//"
+}
+
 # Usage: _login
 _login() {
   WORLD4YOU_USERNAME="${WORLD4YOU_USERNAME:-$(_readaccountconf_mutable WORLD4YOU_USERNAME)}"