test: fix flaky GUI protect test — deterministic tab navigation (#64)

Gui_ProtectSampleApp_ShowsSuccess intermittently failed at the Protect!
button lookup (~1 in 3 runs). Two root causes:

1. ByText("Protect!") ambiguously matched both the tab header and the
   Protect! button (they share the caption), so the wrong element could
   be clicked and the tab never actually got selected.
2. WPF virtualizes inactive tab content — the Protect! button does not
   enter the UIA tree until the tab is selected AND rendered. The 5s
   button-find timeout was too short under load.

Fix: match the tab by TabItem control type + name, Select() it and wait
for IsSelected, then find the button with a 15s timeout. 5/5 consecutive
full-suite runs now pass 3/3 (previously ~1/3 failed).

Author: RandomCrocodile

Tests/Confuser.GUI.Test/GuiSmokeTest.cs

@@ -150,15 +150,28 @@ public void Gui_ProtectSampleApp_ShowsSuccess() {
 				LaunchGui($"\"{crprojPath}\"");
 				var mainWindow = WaitForMainWindow(app);
 
-				// Navigate to the Protect! tab
+				// Navigate to the Protect! tab. Match by TabItem control type + name —
+				// NOT ByText, which ambiguously matches both the tab header and the
+				// Protect! button (they share the caption "Protect!").
 				var protectTab = Retry.WhileNull(
-					() => mainWindow.FindFirstDescendant(cf => cf.ByText("Protect!")),
-					TimeSpan.FromSeconds(5),
-					TimeSpan.FromMilliseconds(500)).Result;
+					() => mainWindow.FindFirstDescendant(cf =>
+						cf.ByControlType(FlaUI.Core.Definitions.ControlType.TabItem)
+						  .And(cf.ByName("Protect!"))),
+					TimeSpan.FromSeconds(10),
+					TimeSpan.FromMilliseconds(300)).Result;
 				Assert.NotNull(protectTab);
-				protectTab.Click();
 
-				// Find and click the Protect! button
+				// Select the tab and wait until it is actually selected. WPF virtualizes
+				// inactive tab content, so the Protect! button does not enter the UIA tree
+				// until the tab is selected and its content has rendered.
+				var tabItem = protectTab.AsTabItem();
+				tabItem.Select();
+				Retry.WhileFalse(
+					() => tabItem.IsSelected,
+					TimeSpan.FromSeconds(5),
+					TimeSpan.FromMilliseconds(200));
+
+				// Find and click the Protect! button (only present once the tab is rendered).
 				var protectButton = Retry.WhileNull(
 					() => {
 						var buttons = mainWindow.FindAllDescendants(cf => cf.ByControlType(FlaUI.Core.Definitions.ControlType.Button));
@@ -167,8 +180,8 @@ public void Gui_ProtectSampleApp_ShowsSuccess() {
 						}
 						return null;
 					},
-					TimeSpan.FromSeconds(5),
-					TimeSpan.FromMilliseconds(500)).Result;
+					TimeSpan.FromSeconds(15),
+					TimeSpan.FromMilliseconds(300)).Result;
 
 				Assert.NotNull(protectButton);
 				output.WriteLine("Clicking Protect! button...");