Move Swap to connect row, show limiter values, fix trackbar keys

- Swap checkbox moved up to the Connect/device line
- Limiter values shown as separate labels (plain, 32px wide for 3 digits)
- Trackbar keyboard: Up/PageUp/Home = increase, Down/PageDown/End = decrease
- Fix Lim B trackbar clipping (moved down to avoid overlap with Lim A)

MainForm.cs

@@ -36,8 +36,11 @@ public class MainForm : Form
     readonly TrackBar _limitBarB;
     readonly Label _lblLimitA;
     readonly Label _lblLimitB;
+    readonly Label _lblLimitValA;
+    readonly Label _lblLimitValB;
     readonly CheckBox _chkScaleA;
     readonly CheckBox _chkScaleB;
+    readonly CheckBox _chkSwap;
 
     readonly Icon _iconNeutral;
     readonly Icon _iconActive;
@@ -58,7 +61,7 @@ public class MainForm : Form
         _loopCts = new CancellationTokenSource();
 
         Text = $"Substation {typeof(MainForm).Assembly.GetName().Version}";
-        ClientSize = new Size(420, 410);
+        ClientSize = new Size(420, 425);
         FormBorderStyle = FormBorderStyle.FixedSingle;
         MaximizeBox = false;
         StartPosition = FormStartPosition.CenterScreen;
@@ -96,11 +99,20 @@ public class MainForm : Form
         _btnConnect = new Button
         {
             Text = "Connect",
-            Location = new Point(296, 64),
+            Location = new Point(236, 64),
-            Size = new Size(108, 24)
+            Size = new Size(80, 24)
         };
         _btnConnect.Click += OnConnect;
 
+        _chkSwap = new CheckBox
+        {
+            Text = "Swap",
+            Location = new Point(328, 66),
+            Size = new Size(56, 20),
+            Checked = false
+        };
+        _chkSwap.CheckedChanged += OnSwapChanged;
+
         _btnTest = new Button
         {
             Text = "Test",
@@ -190,25 +202,33 @@ public class MainForm : Form
 
         _lblLimitA = new Label
         {
-            Text = "Lim A: 30",
+            Text = "Lim A",
             Location = new Point(16, 274),
-            Size = new Size(56, 20),
+            Size = new Size(40, 20),
             Font = new Font(Font.FontFamily, 9, FontStyle.Bold)
         };
         _limitBarA = new TrackBar
         {
-            Location = new Point(72, 270),
+            Location = new Point(60, 270),
-            Size = new Size(250, 45),
+            Size = new Size(220, 45),
             Minimum = 0,
             Maximum = 200,
             TickFrequency = 50,
             Value = 30
         };
         _limitBarA.ValueChanged += OnLimitChanged;
+        FixTrackbarKeys(_limitBarA);
+        _lblLimitValA = new Label
+        {
+            Text = "30",
+            Location = new Point(286, 274),
+            Size = new Size(32, 20),
+            TextAlign = ContentAlignment.MiddleRight
+        };
         _chkScaleA = new CheckBox
         {
             Text = "Scale",
-            Location = new Point(328, 274),
+            Location = new Point(320, 274),
             Size = new Size(76, 24),
             Checked = false
         };
@@ -216,32 +236,40 @@ public class MainForm : Form
 
         _lblLimitB = new Label
         {
-            Text = "Lim B: 30",
+            Text = "Lim B",
-            Location = new Point(16, 312),
+            Location = new Point(16, 322),
-            Size = new Size(56, 20),
+            Size = new Size(40, 20),
             Font = new Font(Font.FontFamily, 9, FontStyle.Bold)
         };
         _limitBarB = new TrackBar
         {
-            Location = new Point(72, 308),
+            Location = new Point(60, 318),
-            Size = new Size(250, 45),
+            Size = new Size(220, 45),
             Minimum = 0,
             Maximum = 200,
             TickFrequency = 50,
             Value = 30
         };
         _limitBarB.ValueChanged += OnLimitChanged;
+        FixTrackbarKeys(_limitBarB);
+        _lblLimitValB = new Label
+        {
+            Text = "30",
+            Location = new Point(286, 322),
+            Size = new Size(32, 20),
+            TextAlign = ContentAlignment.MiddleRight
+        };
         _chkScaleB = new CheckBox
         {
             Text = "Scale",
-            Location = new Point(328, 312),
+            Location = new Point(320, 322),
             Size = new Size(76, 24),
             Checked = false
         };
         _chkScaleB.CheckedChanged += OnLimitChanged;
         OnLimitChanged(null, EventArgs.Empty);
 
-        Controls.AddRange(new Control[] { _lblBle, _lblWs, _lblDeviceName, _txtDeviceName, _btnConnect, _btnTest, _btnMusic, _btnStop, _lblTrack, _lblSendA, _heatA, _lblSendB, _heatB, _lblRecvA, _gaugeRecvA, _lblRecvB, _gaugeRecvB, _lblLimitA, _limitBarA, _chkScaleA, _lblLimitB, _limitBarB, _chkScaleB });
+        Controls.AddRange(new Control[] { _lblBle, _lblWs, _lblDeviceName, _txtDeviceName, _btnConnect, _chkSwap, _btnTest, _btnMusic, _btnStop, _lblTrack, _lblSendA, _heatA, _lblSendB, _heatB, _lblRecvA, _gaugeRecvA, _lblRecvB, _gaugeRecvB, _lblLimitA, _limitBarA, _lblLimitValA, _chkScaleA, _lblLimitB, _limitBarB, _lblLimitValB, _chkScaleB });
 
         // Tray icon — three cached variants: neutral=gray, active=gold, hot=red-orange
         _iconNeutral = CreateVoltageIcon(Color.Gray);
@@ -401,6 +429,7 @@ public class MainForm : Form
         if (IsDisposed) return;
         BeginInvoke(() =>
         {
+            if (_state.SwapChannels) (a, b) = (b, a);
             _gaugeRecvA.Value = Math.Clamp(a, 0, 200);
             _gaugeRecvB.Value = Math.Clamp(b, 0, 200);
         });
@@ -501,8 +530,13 @@ public class MainForm : Form
         var modeB = _chkScaleB.Checked ? LimitMode.Scale : LimitMode.Clamp;
         _state.SetLimitA(maxA, modeA);
         _state.SetLimitB(maxB, modeB);
-        _lblLimitA.Text = $"Lim A: {maxA}";
+        _lblLimitValA.Text = $"{maxA}";
-        _lblLimitB.Text = $"Lim B: {maxB}";
+        _lblLimitValB.Text = $"{maxB}";
+    }
+
+    void OnSwapChanged(object? sender, EventArgs e)
+    {
+        _state.SwapChannels = _chkSwap.Checked;
     }
 
     string _musicFilePath = "";
@@ -620,6 +654,23 @@ public class MainForm : Form
         };
     }
 
+    static void FixTrackbarKeys(TrackBar tb)
+    {
+        tb.KeyDown += (s, e) =>
+        {
+            if (s is not TrackBar t) return;
+            int step = e.KeyCode == Keys.Up || e.KeyCode == Keys.Down ? 1
+                     : e.KeyCode == Keys.PageUp || e.KeyCode == Keys.PageDown ? 10
+                     : 0;
+            if (step == 0) return;
+            if (e.KeyCode is Keys.Up or Keys.PageUp or Keys.Home)
+                t.Value = Math.Min(t.Maximum, t.Value + (e.KeyCode == Keys.Home ? t.Maximum : step));
+            else
+                t.Value = Math.Max(t.Minimum, t.Value - (e.KeyCode == Keys.End ? t.Maximum : step));
+            e.Handled = true;
+        };
+    }
+
     static Icon CreateVoltageIcon(Color boltColor)
     {
         const int sz = 32;

State.cs

@@ -25,6 +25,7 @@ public class State
     public int MaxB = 200;
     public LimitMode LimitModeA = LimitMode.Clamp;
     public LimitMode LimitModeB = LimitMode.Clamp;
+    public bool SwapChannels;
 
     public void SetLimitA(int max, LimitMode mode)
     {
@@ -129,6 +130,19 @@ public class State
             LastIntensityA = hasA ? (intA[0] + intA[1] + intA[2] + intA[3]) / 4 : 0;
             LastIntensityB = hasB ? (intB[0] + intB[1] + intB[2] + intB[3]) / 4 : 0;
 
+            if (SwapChannels)
+            {
+                (valA, valB) = (valB, valA);
+                (modeA, modeB) = (modeB, modeA);
+                (freqA, freqB) = (freqB, freqA);
+                (intA, intB) = (intB, intA);
+                (LastSentA, LastSentB) = (LastSentB, LastSentA);
+                (LastFreqA, LastFreqB) = (LastFreqB, LastFreqA);
+                (LastIntA, LastIntB) = (LastIntB, LastIntA);
+                (LastActiveA, LastActiveB) = (LastActiveB, LastActiveA);
+                (LastIntensityA, LastIntensityB) = (LastIntensityB, LastIntensityA);
+            }
+
             return (modeA, valA, modeB, valB, freqA, intA, freqB, intB);
         }
     }