Apply WireGuard peers to VPS safely

src/main/java/com/litoralregas/vpnprovisioner/vps/WireGuardVpsService.java

@@ -44,4 +44,25 @@ public class WireGuardVpsService {
 
         return ips;
     }
+
+    public WireGuardPeerApplyResult applyPeer(String publicKey, String allowedIps) {
+
+        String command = """
+            sudo /usr/local/sbin/lr-wg-add-peer '%s' '%s'
+            """.formatted(publicKey, allowedIps);
+
+        SshCommandResult result = sshService.executeOnConfiguredVps(command);
+
+        if (result.exitCode() != 0) {
+            throw new SshCommandException(
+                    "Failed to apply WireGuard peer: " + result.stderr()
+            );
+        }
+
+        return new WireGuardPeerApplyResult(
+                publicKey,
+                allowedIps,
+                true
+        );
+    }
 }