fix: apply imported config selections to lazily-built tabs (#4938)

Tabs other than Install build their checkboxes lazily on first visit.
Import populates $sync.selected* and calls Reset-WPFCheckBoxes, but
that only touches checkboxes that already exist in $sync, so any tab
not yet visited gets its controls built later with default (unchecked)
state and never reflects the import. Re-apply Reset-WPFCheckBoxes right
after a tab's controls are built so it picks up existing selections.

functions/private/Initialize-WinUtilTabContent.ps1

@@ -36,4 +36,7 @@ function Initialize-WinUtilTabContent {
     }
 
     $sync.InitializedTabs[$TabName] = $true
+
+    # Sync freshly built controls to any selections already in $sync.selected* (import/preset).
+    Reset-WPFCheckBoxes -doToggles $true
 }

pester/lazy-tabs.Tests.ps1

@@ -12,6 +12,7 @@ BeforeAll {
         param([string]$TargetGridName)
     }
     function Invoke-WinUtilISOCheckExistingWork { }
+    function Reset-WPFCheckBoxes { param([bool]$doToggles) }
 
     . (Join-Path $script:repoRoot "functions\private\Initialize-WinUtilTabContent.ps1")
 }
@@ -29,6 +30,7 @@ Describe "Initialize-WinUtilTabContent" {
 
         Mock Invoke-WPFUIElements { }
         Mock Initialize-WPFUI { }
+        Mock Reset-WPFCheckBoxes { }
     }
 
     AfterEach {
@@ -51,6 +53,21 @@ Describe "Initialize-WinUtilTabContent" {
         $script:sync.InitializedTabs["Install"] | Should -BeTrue
     }
 
+    It "re-applies checkbox selections after building a tab's controls" {
+        Initialize-WinUtilTabContent -TabName "Tweaks"
+
+        Should -Invoke -CommandName Reset-WPFCheckBoxes -Times 1 -Exactly -ParameterFilter {
+            $doToggles -eq $true
+        }
+    }
+
+    It "does not re-apply checkbox selections on a tab that's already built" {
+        Initialize-WinUtilTabContent -TabName "Tweaks"
+        Initialize-WinUtilTabContent -TabName "Tweaks"
+
+        Should -Invoke -CommandName Reset-WPFCheckBoxes -Times 1 -Exactly
+    }
+
     It "initializes deferred config-backed tabs once" {
         Initialize-WinUtilTabContent -TabName "Tweaks"
         Initialize-WinUtilTabContent -TabName "Config"