fix: RGB watchdog — 15s interval, explicit disconnect before reconnect

Root cause: watchdog reconnected every 5s without closing old socket,

creating 100+ TIME_WAIT connections that exhausted ephemeral ports.

- Watchdog interval: 5s -> 15s (reduces TIME_WAIT pressure)

- Explicit Disconnect() call before ConnectAsync() in watchdog

- Overlay defaults: transparent=false, topmost=false (already pushed)

Author: AntwerpDesignsIonity

src/Fanzi.FanControl/ViewModels/RgbControlViewModel.cs

@@ -386,11 +386,14 @@ private async Task ConnectionWatchdogAsync(CancellationToken token)
         {
             try
             {
-                await Task.Delay(5000, token);
+                await Task.Delay(15000, token);
                 if (!RgbEnabled || _autoStartInProgress) continue;
 
                 if (!_rgbService.IsConnected && OpenRgbServerManager.IsPortListening(OpenRgbPort))
                 {
+                    // Properly dispose the old client BEFORE reconnecting —
+                    // prevents socket leak and TIME_WAIT accumulation.
+                    _rgbService.Disconnect();
                     ConnectionStatus = "AEDi: Reconnecting...";
                     await ConnectAsync();
                     if (IsConnected)