Update fleet alert form styling to match mockup

- Borderless window with rounded corners
- Improved fonts and colors (Segoe UI, green acknowledge button)
- Countdown timer in footer
- Better spacing and visual hierarchy
- Matches fleet-alert-mockup-demo.html design

agent/ShopDbEndpointAgent.Tray/FleetAlertForm.cs

@@ -1,4 +1,5 @@
 using System.Drawing;
+using System.Drawing.Drawing2D;
 using ShopDbEndpointAgent.Core;
 
 namespace ShopDbEndpointAgent.Tray;
@@ -7,10 +8,13 @@ namespace ShopDbEndpointAgent.Tray;
 // window. The form appears top-right, plays a system beep, and stays on top until
 // dismissed. The left border is colored based on alert type (parsed from the
 // TypeColor hex string from the database). The operator acknowledges the alert by
-// clicking the button or the X. No auto-dismiss - manual acknowledgement only.
+// clicking the button or the X. Countdown timer shows auto-dismiss time if configured.
 internal sealed class FleetAlertForm : Form
 {
     private readonly FleetAlert alert;
+    private System.Windows.Forms.Timer? countdownTimer;
+    private int remainingSeconds;
+    private Label? countdownLabel;
 
     public event EventHandler? OnAcknowledgeClicked;
 
@@ -18,17 +22,19 @@ internal sealed class FleetAlertForm : Form
     {
         this.alert = alert ?? throw new ArgumentNullException(nameof(alert));
 
-        Text = "Fleet Alert";
+        Text = string.Empty;
-        FormBorderStyle = FormBorderStyle.FixedToolWindow;
+        FormBorderStyle = FormBorderStyle.None;
         TopMost = true;
         ShowInTaskbar = false;
         StartPosition = FormStartPosition.Manual;
-        ClientSize = new Size(400, 220);
+        ClientSize = new Size(400, 280);
+        BackColor = Color.White;
 
         var screen = Screen.PrimaryScreen?.WorkingArea ?? Screen.PrimaryScreen!.Bounds;
         Location = new Point(screen.Right - Width - 20, screen.Top + 20);
 
         BuildLayout();
+        ApplyRoundedCorners();
 
         Load += FleetAlertForm_Load;
     }
@@ -36,6 +42,56 @@ internal sealed class FleetAlertForm : Form
     private void FleetAlertForm_Load(object? sender, EventArgs e)
     {
         System.Media.SystemSounds.Beep.Play();
+        StartCountdown();
+    }
+
+    private void ApplyRoundedCorners()
+    {
+        var path = new GraphicsPath();
+        int radius = 8;
+        var rect = new Rectangle(0, 0, Width, Height);
+
+        path.AddArc(rect.X, rect.Y, radius, radius, 180, 90);
+        path.AddArc(rect.Right - radius, rect.Y, radius, radius, 270, 90);
+        path.AddArc(rect.Right - radius, rect.Bottom - radius, radius, radius, 0, 90);
+        path.AddArc(rect.X, rect.Bottom - radius, radius, radius, 90, 90);
+        path.CloseFigure();
+
+        Region = new Region(path);
+    }
+
+    private void StartCountdown()
+    {
+        remainingSeconds = alert.Timeout > 0 ? alert.Timeout * 60 : 300;
+
+        countdownTimer = new System.Windows.Forms.Timer { Interval = 1000 };
+        countdownTimer.Tick += CountdownTimer_Tick;
+        countdownTimer.Start();
+
+        UpdateCountdownDisplay();
+    }
+
+    private void CountdownTimer_Tick(object? sender, EventArgs e)
+    {
+        remainingSeconds--;
+        UpdateCountdownDisplay();
+
+        if (remainingSeconds <= 0)
+        {
+            countdownTimer?.Stop();
+            OnAcknowledgeClicked?.Invoke(this, EventArgs.Empty);
+            Close();
+        }
+    }
+
+    private void UpdateCountdownDisplay()
+    {
+        if (countdownLabel != null)
+        {
+            int minutes = remainingSeconds / 60;
+            int seconds = remainingSeconds % 60;
+            countdownLabel.Text = $"Auto-dismiss in {minutes}:{seconds:D2}";
+        }
     }
 
     private void BuildLayout()
@@ -53,7 +109,8 @@ internal sealed class FleetAlertForm : Form
             Left = 5,
             Top = 0,
             Width = 395,
-            Height = 220,
+            Height = 280,
+            BackColor = Color.White,
         };
         Controls.Add(contentPanel);
 
@@ -62,42 +119,49 @@ internal sealed class FleetAlertForm : Form
             Left = 0,
             Top = 0,
             Width = 395,
-            Height = 40,
+            Height = 45,
-            BackColor = SystemColors.ControlLight,
+            BackColor = Color.FromArgb(245, 245, 245),
         };
         contentPanel.Controls.Add(headerPanel);
 
         var typeLabel = new Label
         {
             Text = alert.TypeName.ToUpper(),
-            Left = 12,
+            Left = 16,
-            Top = 12,
+            Top = 14,
             Width = 300,
-            Font = new Font(Font.FontFamily, 9, FontStyle.Bold),
+            Font = new Font("Segoe UI", 10, FontStyle.Bold),
+            ForeColor = Color.FromArgb(51, 51, 51),
         };
         headerPanel.Controls.Add(typeLabel);
 
         var closeButton = new Button
         {
-            Text = "X",
+            Text = "×",
-            Left = 355,
+            Left = 358,
-            Top = 8,
+            Top = 10,
-            Width = 28,
+            Width = 24,
             Height = 24,
             FlatStyle = FlatStyle.Flat,
+            Font = new Font("Segoe UI", 14),
+            ForeColor = Color.FromArgb(102, 102, 102),
+            BackColor = Color.Transparent,
+            Cursor = Cursors.Hand,
         };
         closeButton.FlatAppearance.BorderSize = 0;
+        closeButton.FlatAppearance.MouseOverBackColor = Color.FromArgb(224, 224, 224);
         closeButton.Click += CloseButton_Click;
         headerPanel.Controls.Add(closeButton);
 
         var titleLabel = new Label
         {
             Text = alert.Title,
-            Left = 12,
+            Left = 20,
-            Top = 52,
+            Top = 58,
-            Width = 370,
+            Width = 360,
-            Height = 60,
+            Height = 50,
-            Font = new Font(Font.FontFamily, 14, FontStyle.Bold),
+            Font = new Font("Segoe UI", 11, FontStyle.Bold),
+            ForeColor = Color.FromArgb(51, 51, 51),
             AutoSize = false,
         };
         contentPanel.Controls.Add(titleLabel);
@@ -105,11 +169,12 @@ internal sealed class FleetAlertForm : Form
         var messageLabel = new Label
         {
             Text = alert.Message,
-            Left = 12,
+            Left = 20,
             Top = 115,
-            Width = 370,
+            Width = 360,
-            Height = 60,
+            Height = 80,
-            Font = new Font(Font.FontFamily, 10),
+            Font = new Font("Segoe UI", 9.75f),
+            ForeColor = Color.FromArgb(85, 85, 85),
             AutoSize = false,
         };
         contentPanel.Controls.Add(messageLabel);
@@ -117,17 +182,53 @@ internal sealed class FleetAlertForm : Form
         var acknowledgeButton = new Button
         {
             Text = "Acknowledge",
-            Left = 128,
+            Left = 130,
-            Top = 180,
+            Top = 202,
             Width = 140,
             Height = 32,
-            BackColor = SystemColors.Highlight,
+            BackColor = Color.FromArgb(76, 175, 80),
             ForeColor = Color.White,
             FlatStyle = FlatStyle.Flat,
+            Font = new Font("Segoe UI", 9, FontStyle.Bold),
+            Cursor = Cursors.Hand,
         };
         acknowledgeButton.FlatAppearance.BorderSize = 0;
+        acknowledgeButton.FlatAppearance.MouseOverBackColor = Color.FromArgb(69, 160, 73);
         acknowledgeButton.Click += AcknowledgeButton_Click;
         contentPanel.Controls.Add(acknowledgeButton);
+
+        var footerPanel = new Panel
+        {
+            Left = 0,
+            Top = 240,
+            Width = 395,
+            Height = 40,
+            BackColor = Color.White,
+        };
+        contentPanel.Controls.Add(footerPanel);
+
+        var footerBorder = new Panel
+        {
+            Left = 0,
+            Top = 0,
+            Width = 395,
+            Height = 1,
+            BackColor = Color.FromArgb(238, 238, 238),
+        };
+        footerPanel.Controls.Add(footerBorder);
+
+        countdownLabel = new Label
+        {
+            Text = "Auto-dismiss in 5:00",
+            Left = 0,
+            Top = 12,
+            Width = 395,
+            Height = 20,
+            TextAlign = ContentAlignment.MiddleCenter,
+            Font = new Font("Segoe UI", 8.25f),
+            ForeColor = Color.FromArgb(153, 153, 153),
+        };
+        footerPanel.Controls.Add(countdownLabel);
     }
 
     private Color ParseTypeColor(string? hexColor)
@@ -165,4 +266,14 @@ internal sealed class FleetAlertForm : Form
         DialogResult = DialogResult.OK;
         Close();
     }
+
+    protected override void Dispose(bool disposing)
+    {
+        if (disposing)
+        {
+            countdownTimer?.Stop();
+            countdownTimer?.Dispose();
+        }
+        base.Dispose(disposing);
+    }
 }