fix: use quotemeta to join command parts

Co-authored-by: Stéphane Lesimple <speed47_github@speed47.net>

bin/shell/osh.pl

@@ -1625,7 +1625,7 @@ else {
         push @proxyCommand, '-o', "ConnectTimeout=$timeout" if $timeout;
 
         # Quote arguments that contain spaces and build the command string
-        my $proxyCommandStr = join(' ', map { /\s/ ? "'$_'" : $_ } @proxyCommand);
+        my $proxyCommandStr = join(' ', map { quotemeta } @proxyCommand);
         push @command, '-o', "ProxyCommand=$proxyCommandStr";
 
         osh_debug("ProxyCommand: $proxyCommandStr");