web: keep stored config lines and per-port ingress when saving

Save to flash ran the stored config through the same filter as the
command log, so stored lines the page does not know were dropped. The
stored lines are now carried over as they are and only the log is
filtered.

ingress only changes the ports it lists, but the merge replaced every
stored ingress line. It now merges per port; "ingress t|u|a" still
replaces everything, and per-port settings an all-ports line already
overrode are not revived.

Write from the config editor no longer clears the command log or the
unsaved marker, since the edited text does not hold the changes made on
other pages; only Save, which merges them, clears the log.

The command log grows from 1 kB to 2 kB, which still fits the 2500 byte
output buffer, and send_cmd_log() stops at the end of that buffer.

httpd/page_impl.c

@@ -990,7 +990,7 @@ void send_cmd_log(void)
 	__xdata uint8_t found_begin = 0;
 	dbg_string("History ptr: ");
 	dbg_short(cmd_history_ptr); dbg_char('\n');
-	while (p != cmd_history_ptr) {
+	while (p != cmd_history_ptr && slen < TCP_OUTBUF_SIZE) {
 		if (!cmd_history[p] || cmd_history[p] == '\n')
 			found_begin = 1;
 		if (found_begin && cmd_history[p])