Disable auto-dismiss timer for fleet alerts

- Remove countdown timer startup
- Change footer text to 'Manual acknowledgment required'
- Bump tray version to 1.6.2

agent/ShopDbEndpointAgent.Tray/FleetAlertForm.cs

@@ -48,7 +48,6 @@ internal sealed class FleetAlertForm : Form
     private void FleetAlertForm_Load(object? sender, EventArgs e)
     {
         System.Media.SystemSounds.Beep.Play();
-        StartCountdown();
     }
 
     private void ApplyRoundedCorners()
@@ -225,7 +224,7 @@ internal sealed class FleetAlertForm : Form
 
         countdownLabel = new Label
         {
-            Text = "Auto-dismiss in 5:00",
+            Text = "Manual acknowledgment required",
             Left = 0,
             Top = 12,
             Width = 395,

agent/ShopDbEndpointAgent.Tray/ShopDbEndpointAgent.Tray.csproj

@@ -73,7 +73,10 @@
 			  immediate", not "session data stops working". Requires agent 1.11.0. -->
 		 <!-- 1.6.1: fix crash when clicking acknowledge button. The countdown timer
 	     is now properly stopped before the form closes to prevent disposal issues. -->
-	<Version>1.6.1</Version>
+	<!-- 1.6.2: disable auto-dismiss timer. Fleet alerts now require manual
+	     acknowledgment only. Footer shows "Manual acknowledgment required" instead
+	     of countdown timer. -->
+	<Version>1.6.2</Version>
 	<InvariantGlobalization>true</InvariantGlobalization>
 	<RuntimeIdentifier>win-x64</RuntimeIdentifier>
 	<SelfContained>true</SelfContained>