fix(msi): ship WinUI 3 GUI; pick host-arch makepri.exe

build.ps1

@@ -1165,8 +1165,18 @@ function Publish-AppResources {
         "${env:ProgramFiles(x86)}\Windows Kits\10\bin"
     ) | Where-Object { Test-Path $_ }
 
+    # makepri.exe runs on the HOST, not the target. Prefer the host arch first
+    # so we don't pick e.g. arm64\makepri.exe on an x64 box (which fails with
+    # "not a valid application for this OS platform").
+    $hostArch = switch ($env:PROCESSOR_ARCHITECTURE) {
+        'AMD64' { 'x64' }
+        'ARM64' { 'arm64' }
+        default { 'x86' }
+    }
+    $toolArchOrder = @($hostArch) + (@('x64','arm64','x86') | Where-Object { $_ -ne $hostArch })
+
     foreach ($root in $sdkBinRoots) {
-        foreach ($toolArch in @("arm64", "x64", "x86")) {
+        foreach ($toolArch in $toolArchOrder) {
             $candidates = Get-ChildItem "$root\*\$toolArch\makepri.exe" -ErrorAction SilentlyContinue |
                 Sort-Object { [version]($_.FullName -replace '.*\\(\d+\.\d+\.\d+\.\d+)\\.*', '$1') } -Descending |
                 Select-Object -First 1

installer/BootstrapMate.Installer.wixproj

@@ -29,9 +29,33 @@
     <PackageReference Include="WixToolset.Util.wixext" Version="6.0.2" />
   </ItemGroup>
 
+  <!-- Suppress ICE03 (Invalid Language Id / String overflow in File.Language).
+       The WinUI 3 MUI files harvested from publish/app/<arch>/ include locales
+       (gd-gb, mi-NZ) whose LCIDs are not in the ICE validation table, and the
+       master Microsoft.ui.xaml.dll has more locales than the File.Language
+       column's 255-char limit. Both are benign for actual install/uninstall. -->
+  <PropertyGroup>
+    <SuppressIces>ICE03</SuppressIces>
+  </PropertyGroup>
+
+  <!-- Skip when the GUI publish output is missing — the BeforeBuild target
+       below will then fail with a clearer, more actionable message rather
+       than the harvester script's stack trace. -->
+  <Target Name="GenerateGuiAppFiles"
+          BeforeTargets="BeforeBuild"
+          Condition="Exists('$(AppDir)\BootstrapMate.exe')">
+    <MakeDir Directories="$(IntermediateOutputPath)" />
+    <Exec Command="pwsh -NoProfile -ExecutionPolicy Bypass -File &quot;$(MSBuildProjectDirectory)\Generate-GuiAppFiles.ps1&quot; -AppDir &quot;$(AppDir)&quot; -OutputPath &quot;$(IntermediateOutputPath)GuiAppFiles.wxs&quot;" />
+    <ItemGroup>
+      <Compile Include="$(IntermediateOutputPath)GuiAppFiles.wxs" />
+    </ItemGroup>
+  </Target>
+
   <Target Name="BeforeBuild">
     <Error Text="BootstrapMate executable not found at $(BinDir)\installapplications.exe. Please run build.ps1 first."
            Condition="!Exists('$(BinDir)\installapplications.exe')" />
+    <Error Text="BootstrapMate GUI app executable not found at $(AppDir)\BootstrapMate.exe. Run build.ps1 to publish the GUI before building the MSI."
+           Condition="!Exists('$(AppDir)\BootstrapMate.exe')" />
   </Target>
 
 </Project>

installer/Generate-GuiAppFiles.ps1

@@ -29,13 +29,20 @@ $lines.Add('  <Fragment>')
 $lines.Add('    <ComponentGroup Id="GuiAppFiles" Directory="INSTALLDIR">')
 
 $files = Get-ChildItem -Path $appDir -Recurse -File | Sort-Object FullName
-$idx = 0
+$sha1  = [System.Security.Cryptography.SHA1]::Create()
 foreach ($file in $files) {
-    $idx++
     $relPath = $file.FullName.Substring($appDir.Length + 1)
     $relDir  = [System.IO.Path]::GetDirectoryName($relPath)
-    $compId  = 'c_{0:D5}' -f $idx
-    $fileId  = 'f_{0:D5}' -f $idx
+
+    # Deterministic IDs derived from a SHA1 hash of the relative path so that
+    # unchanged files keep the same Component Id (and therefore the same
+    # Guid="*"-derived GUID) across builds. Sequential IDs would shift whenever
+    # files are added/removed (e.g. WinUI 3 ships a new locale), regenerating
+    # most GUIDs and breaking MSI upgrade tracking — orphaning old components
+    # or duplicating files at the same path.
+    $hashHex = [System.BitConverter]::ToString($sha1.ComputeHash([System.Text.Encoding]::UTF8.GetBytes($relPath.ToLowerInvariant()))).Replace('-','').Substring(0,16).ToLowerInvariant()
+    $compId  = "c_$hashHex"
+    $fileId  = "f_$hashHex"
 
     if ($relDir) {
         $lines.Add("      <Component Id=`"$compId`" Guid=`"*`" Subdirectory=`"$relDir`">")

installer/Product.wxs

@@ -43,11 +43,9 @@
       <RemoveFile Id="RemoveOldExecutable" Name="installapplications.exe" On="both" />
     </Component>
 
-    <!-- GUI Application -->
-    <Component Id="BootstrapMateGuiApp" Directory="INSTALLDIR" Guid="F1A2B3C4-D5E6-7890-ABCD-EF1234567890"
-               Condition="APP_DIR &lt;&gt; &quot;&quot;">
-      <File Id="BootstrapMateGuiExe" Source="$(var.APP_DIR)\BootstrapMate.exe" Vital="yes" />
-    </Component>
+    <!-- GUI Application files (BootstrapMate.exe + WinUI 3 dependencies) are
+         harvested from $(var.APP_DIR) into the GuiAppFiles ComponentGroup by
+         the Generate-GuiAppFiles.ps1 pre-build target in the wixproj. -->
 
     <!-- Registry entries for installation tracking AND detection -->
     <Component Id="RegistryEntries" Directory="INSTALLDIR" Guid="E5F6A7B8-C9D0-1234-EF56-789012345ABC">
@@ -79,7 +77,7 @@
     <!-- Feature Definition -->
     <Feature Id="DefaultFeature" Level="1">
       <ComponentRef Id="BootstrapMateExecutable" />
-      <ComponentRef Id="BootstrapMateGuiApp" />
+      <ComponentGroupRef Id="GuiAppFiles" />
       <ComponentRef Id="RegistryEntries" />
       <ComponentRef Id="SetPathComponent" />
     </Feature>