Add localization framework for the GUI (en-US baseline) (#764)

Credit to @jmolinap2 for their work in #643, which was used as inspiration.

Scripts/GUI/MainWindow-Deployment.ps1

@@ -96,6 +96,17 @@ function Get-PendingTweakActions {
     return @($actions.ToArray())
 }
 
+<#
+    .SYNOPSIS
+        Builds the plain-text list of pending changes: apps to remove and tweaks to apply or undo.
+
+    .PARAMETER ShowCurrentlyAppliedTweaksCheckBox
+        When checked, pending tweak actions are computed against the system's live applied
+        state instead of the controls' initial values.
+
+    .OUTPUTS
+        System.String[]. One line per pending change, or an empty array if nothing is selected.
+#>
 function New-Overview {
     param(
         [System.Windows.Window]$Window,
@@ -114,12 +125,12 @@ function New-Overview {
         }
     }
     if ($selectedAppsCount -gt 0) {
-        $changesList += "Remove $selectedAppsCount application(s)"
+        $changesList += Get-Translation -Key 'DeployChangeRemoveApps' -Count $selectedAppsCount -FormatArgs @($selectedAppsCount)
     }
 
     foreach ($tweakAction in @(Get-PendingTweakActions -Window $Window -ShowAppliedTweaksMode:$showAppliedTweaksMode)) {
         if ($tweakAction.Action -eq 'Undo') {
-            $changesList += "Undo: $($tweakAction.Label)"
+            $changesList += Get-Translation -Key 'DeployChangeUndoPrefix' -FormatArgs @($tweakAction.Label)
         }
         else {
             $changesList += $tweakAction.Label
@@ -129,6 +140,11 @@ function New-Overview {
     return $changesList
 }
 
+<#
+    .SYNOPSIS
+        Shows the pending-changes list from New-Overview in a message box, or a
+        "no changes selected" message when there's nothing to show.
+#>
 function Invoke-ShowChangesOverview {
     param(
         [System.Windows.Window]$Window,
@@ -139,12 +155,12 @@ function Invoke-ShowChangesOverview {
     $changesList = New-Overview -Window $Window -AppsPanel $AppsPanel -ShowCurrentlyAppliedTweaksCheckBox $ShowCurrentlyAppliedTweaksCheckBox
 
     if ($changesList.Count -eq 0) {
-        Show-MessageBox -Message 'No changes have been selected.' -Title 'Selected Changes' -Button 'OK' -Icon 'Information'
+        Show-MessageBox -Message (Get-Translation -Key 'DeployNoChangesSelectedMessage') -Title (Get-Translation -Key 'DeploySelectedChangesTitle') -Button 'OK' -Icon 'Information'
         return
     }
 
     $message = ($changesList | ForEach-Object { "$([char]0x2022) $_" }) -join "`n"
-    Show-MessageBox -Message $message -Title 'Selected Changes' -Button 'OK' -Icon 'None' -Width 600
+    Show-MessageBox -Message $message -Title (Get-Translation -Key 'DeploySelectedChangesTitle') -Button 'OK' -Icon 'None' -Width 600
 }
 
 <#
@@ -437,6 +453,14 @@ function Update-AppliedTweaksUserModeState {
     }
 }
 
+<#
+    .SYNOPSIS
+        Updates the deployment-target description text to match the selected user option.
+
+    .DESCRIPTION
+        Falls back to a generic description (current user, other user, or Sysprep default
+        profile) when a username can't be resolved yet, and to a specific one once it can.
+#>
 function Update-UserSelectionDescription {
     param(
         [System.Windows.Window]$Window,
@@ -449,23 +473,23 @@ function Update-UserSelectionDescription {
         0 {
             $currentUserName = Get-UserName
             if ([string]::IsNullOrWhiteSpace($currentUserName)) {
-                $UserSelectionDescription.Text = "The currently logged-in user profile"
+                $UserSelectionDescription.Text = Get-Translation -Key 'DeployUserDescriptionCurrentUser'
             }
             else {
-                $UserSelectionDescription.Text = "The currently logged-in user profile: $currentUserName"
+                $UserSelectionDescription.Text = Get-Translation -Key 'DeployUserDescriptionCurrentUserNamed' -FormatArgs @($currentUserName)
             }
         }
         1 {
             $targetUserName = $OtherUsernameTextBox.Text.Trim()
             if ([string]::IsNullOrWhiteSpace($targetUserName)) {
-                $UserSelectionDescription.Text = "A different user profile on this system"
+                $UserSelectionDescription.Text = Get-Translation -Key 'DeployUserDescriptionOtherUser'
             }
             else {
-                $UserSelectionDescription.Text = "A different user profile on this system: $targetUserName"
+                $UserSelectionDescription.Text = Get-Translation -Key 'DeployUserDescriptionOtherUserNamed' -FormatArgs @($targetUserName)
             }
         }
         default {
-            $UserSelectionDescription.Text = "The default user template, affecting all new users created after this point. Useful for Sysprep deployment."
+            $UserSelectionDescription.Text = Get-Translation -Key 'DeployUserDescriptionSysprep'
         }
     }