Fix network map duplicate-device bug: drop nmap --send-ip (was causing MAC misattribution/stale ARP entries) and dedupe network_devices by MAC on every scan push so IP changes don't leave orphaned rows

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

agent/pve1-probes/jarvis-netscan.sh

@@ -12,7 +12,7 @@ fi
 SUBNET="10.48.200.0/24"
 
 TMPFILE=$(mktemp)
-nmap -sn --send-ip "$SUBNET" 2>/dev/null > "$TMPFILE"
+nmap -sn "$SUBNET" 2>/dev/null > "$TMPFILE"
 
 if [ ! -s "$TMPFILE" ]; then
     echo "$(date): nmap produced no output" >&2

api/endpoints/netscan.php

@@ -35,6 +35,11 @@ foreach ($devices as $d) {
     if (!$ip) continue;
 
     $discoveredIPs[] = $ip;
+    if ($mac) {
+        // Device likely moved to a new IP (DHCP) — drop the stale row so it
+        // doesn't linger as an orphaned duplicate under the old address.
+        JarvisDB::execute('DELETE FROM network_devices WHERE mac=? AND ip<>?', [$mac, $ip]);
+    }
     JarvisDB::execute(
         'INSERT INTO network_devices (ip, mac, hostname, status, last_seen)
          VALUES (?,?,?,?,NOW())