fix: stabilize installer flows, managers, and terminal output

lib/wireguard.sh

@@ -23,8 +23,12 @@ get_next_wg_ip() {
     if [ -z "$LAST_IP" ]; then
         echo "10.0.0.2"
     else
-        LAST_NUM=$(echo $LAST_IP | cut -d. -f4)
+        LAST_NUM=$(echo "$LAST_IP" | cut -d. -f4)
         NEXT_NUM=$((LAST_NUM + 1))
+        if [ "$NEXT_NUM" -gt 254 ]; then
+            error "Пул адресов WireGuard исчерпан (10.0.0.2-10.0.0.254)"
+            return 1
+        fi
         echo "10.0.0.$NEXT_NUM"
     fi
 }
@@ -147,7 +151,15 @@ remove_wireguard_client() {
         return 0
     fi
 
-    sed -i "/# $client_name/,+2d" $WG_CONF
+    local tmp_conf
+    tmp_conf="$(mktemp)"
+    awk -v marker="# ${client_name}" '
+        BEGIN {skip=0}
+        $0 == marker {skip=1; next}
+        skip && /^\[Peer\]/ {skip=0}
+        !skip {print}
+    ' "$WG_CONF" > "$tmp_conf"
+    mv "$tmp_conf" "$WG_CONF"
     rm -rf "$CLIENT_DIR"
 
     systemctl restart wg-quick@wg0