I configured the web-proxy it’s very good the problem is
if i’m out of my LAN but connected to the internet i can use my internet connection if i set my public ip as the proxy and the port I Set… so 
PPL can use my proxy server for anonyme surfing
1 - so i want to Stop the use of the web-proxy and restrict it only for my LAN
2 - also i want to stop the use of the internet in my LAN without proxy
You should construct rules, similar to firewall rules, in /ip proxy access. Instructions are here.
I don’t have any experience with proxy, but from documentation I presume you should set something like this:
/ip proxy access
add action=allow src-address=<LAN v4 address>/<mask>
#add action=allow src-address=<LAN v6 address>/<mask>
add action=deny
If you’re using default settings, then src-address in the first allow rule would be 192.168.88.0/24. If you also use IPv6, then find out prefix your ISP delegated to you and construct similar allow rule using that prefix for IPv6.
Rules are evaluated from to to bottom, hence whatever not explicitly allowed by earlier rules gets denied by last rule.
Another possibility is to limit access to proxy (allow it only from LAN) by constructing appropriate firewall filter rule. However, if proxy service is currently available from internet, then you deviated from default firewall filter ruleset (which is pretty decent and doesn’t allow access to any router service from internet side) and you probably should fix more than only access to proxy.