fix(release): Upgrade WiX from v4.0.0-preview.0 to v6.0.2 stable

The WiX build was failing due to several WiX v4 to v6 migration issues.

Workflow changes:
- Uninstall existing WiX before installing v6.0.2 (force clean install)
- WiX version: 4.0.0-preview.0 -> 6.0.2
- Extension: WixToolset.UI.wixext/4.0.0-preview.0 -> WixToolset.UI.wixext/6.0.2
- Fixed extension command syntax: "extension -g add" -> "extension add -g"

installer.wxs changes (WiX v6 migration):
- Added ui namespace: xmlns:ui="http://wixtoolset.org/schemas/v4/wxs/ui"
- Replaced custom inline UI with standard <ui:WixUI Id="WixUI_InstallDir">
  (fixes WIX0094 error for WixUIValidatePath custom action)
- Changed Directory to StandardDirectory for DesktopFolder (fixes WIX5437)

See: https://github.com/orgs/wixtoolset/discussions/6516
     wixtoolset/issues#6998

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: cfsmp3

.github/workflows/release.yml

@@ -65,9 +65,9 @@ jobs:
       run: mkdir installer; cp ./x64/Release-Full/ccextractorwinfull.exe ./installer; cp ./x64/Release-Full/*.dll ./installer
       working-directory: ./windows
     - name: install WiX
-      run: dotnet tool install --global wix --version 4.0.0-preview.0 &&  wix extension -g add WixToolset.UI.wixext
+      run: dotnet tool uninstall --global wix; dotnet tool install --global wix --version 6.0.2 && wix extension add -g WixToolset.UI.wixext/6.0.2
     - name: Make sure WiX works
-      run: wix --version && wix extension -g list
+      run: wix --version && wix extension list -g
     - name: Download Flutter GUI
       run: ((Invoke-WebRequest -UseBasicParsing https://api.github.com/repos/CCExtractor/ccextractorfluttergui/releases/latest).Content | ConvertFrom-Json).assets | ForEach-Object {if ($_.name -eq "windows.zip") { Invoke-WebRequest -UseBasicParsing -Uri $_.browser_download_url -OutFile windows.zip}}
       working-directory: ./windows

windows/installer.wxs

@@ -1,4 +1,4 @@
-<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs" xmlns:ui="http://wixtoolset.org/schemas/v4/wxs/ui">
 	<Package Name="CCExtractor" Language="1033" Version="$(AppVersion)" Manufacturer="CCExtractor development" UpgradeCode="e70dbe37-bb04-4c39-bedc-966a6b073bcf" InstallerVersion="200">
 		<MajorUpgrade DowngradeErrorMessage="A newer version of [ProductName] is already installed."/>
 		<MediaTemplate EmbedCab="yes"/>
@@ -12,58 +12,12 @@
 			<ComponentRef Id="ApplicationShortcutDesktop"/>
 		</Feature>
 		<Icon Id="ccxgui.exe" SourceFile="./installer/ccxgui.exe"/>
-		<!-- Derives from the regular install dir, but skips the license dialog. -->
-		<UI Id="WixUI_InstallDir">
-            <TextStyle Id="WixUI_Font_Normal" FaceName="Tahoma" Size="8" />
-            <TextStyle Id="WixUI_Font_Bigger" FaceName="Tahoma" Size="12" />
-            <TextStyle Id="WixUI_Font_Title" FaceName="Tahoma" Size="9" Bold="yes" />
-
-            <Property Id="DefaultUIFont" Value="WixUI_Font_Normal" />
-            <Property Id="WixUI_Mode" Value="InstallDir" />
-
-            <DialogRef Id="BrowseDlg" />
-            <DialogRef Id="DiskCostDlg" />
-            <DialogRef Id="ErrorDlg" />
-            <DialogRef Id="FatalError" />
-            <DialogRef Id="FilesInUse" />
-            <DialogRef Id="MsiRMFilesInUse" />
-            <DialogRef Id="PrepareDlg" />
-            <DialogRef Id="ProgressDlg" />
-            <DialogRef Id="ResumeDlg" />
-            <DialogRef Id="UserExit" />
-            <Publish Dialog="BrowseDlg" Control="OK" Event="DoAction" Value="WixUIValidatePath" Order="3" />
-            <Publish Dialog="BrowseDlg" Control="OK" Event="SpawnDialog" Value="InvalidDirDlg" Order="4" Condition="NOT WIXUI_DONTVALIDATEPATH AND WIXUI_INSTALLDIR_VALID&lt;&gt;&quot;1&quot;" />
-
-            <Publish Dialog="ExitDialog" Control="Finish" Event="EndDialog" Value="Return" Order="999" />
-
-            <Publish Dialog="WelcomeDlg" Control="Next" Event="NewDialog" Value="InstallDirDlg" Condition="NOT Installed" />
-            <Publish Dialog="WelcomeDlg" Control="Next" Event="NewDialog" Value="VerifyReadyDlg" Condition="Installed AND PATCH" />
-
-            <Publish Dialog="InstallDirDlg" Control="Back" Event="NewDialog" Value="WelcomeDlg" />
-            <Publish Dialog="InstallDirDlg" Control="Next" Event="SetTargetPath" Value="[WIXUI_INSTALLDIR]" Order="1" />
-            <Publish Dialog="InstallDirDlg" Control="Next" Event="DoAction" Value="WixUIValidatePath" Order="2" Condition="NOT WIXUI_DONTVALIDATEPATH" />
-            <Publish Dialog="InstallDirDlg" Control="Next" Event="SpawnDialog" Value="InvalidDirDlg" Order="3" Condition="NOT WIXUI_DONTVALIDATEPATH AND WIXUI_INSTALLDIR_VALID&lt;&gt;&quot;1&quot;" />
-            <Publish Dialog="InstallDirDlg" Control="Next" Event="NewDialog" Value="VerifyReadyDlg" Order="4" Condition="WIXUI_DONTVALIDATEPATH OR WIXUI_INSTALLDIR_VALID=&quot;1&quot;" />
-            <Publish Dialog="InstallDirDlg" Control="ChangeFolder" Property="_BrowseProperty" Value="[WIXUI_INSTALLDIR]" Order="1" />
-            <Publish Dialog="InstallDirDlg" Control="ChangeFolder" Event="SpawnDialog" Value="BrowseDlg" Order="2" />
-            <Publish Dialog="VerifyReadyDlg" Control="Back" Event="NewDialog" Value="InstallDirDlg" Order="1" Condition="NOT Installed" />
-            <Publish Dialog="VerifyReadyDlg" Control="Back" Event="NewDialog" Value="MaintenanceTypeDlg" Order="2" Condition="Installed AND NOT PATCH" />
-            <Publish Dialog="VerifyReadyDlg" Control="Back" Event="NewDialog" Value="WelcomeDlg" Order="2" Condition="Installed AND PATCH" />
-
-            <Publish Dialog="MaintenanceWelcomeDlg" Control="Next" Event="NewDialog" Value="MaintenanceTypeDlg" />
-
-            <Publish Dialog="MaintenanceTypeDlg" Control="RepairButton" Event="NewDialog" Value="VerifyReadyDlg" />
-            <Publish Dialog="MaintenanceTypeDlg" Control="RemoveButton" Event="NewDialog" Value="VerifyReadyDlg" />
-            <Publish Dialog="MaintenanceTypeDlg" Control="Back" Event="NewDialog" Value="MaintenanceWelcomeDlg" />
-
-            <Property Id="ARPNOMODIFY" Value="1" />
-        </UI>
-
-        <UIRef Id="WixUI_Common" />
-		<Property Id="WIXUI_INSTALLDIR" Value="INSTALLFOLDER"/>
+		<!-- Use standard WixUI_InstallDir dialog set -->
+		<ui:WixUI Id="WixUI_InstallDir" InstallDirectory="INSTALLFOLDER" />
+		<Property Id="ARPNOMODIFY" Value="1" />
 	</Package>
 	<Fragment>
-		<Directory Id="DesktopFolder" Name="Desktop">
+		<StandardDirectory Id="DesktopFolder">
         <Component Id="ApplicationShortcutDesktop" Guid="*">
             <Shortcut Id="ApplicationDesktopShortcut"
                 Name="CCExtractor"
@@ -79,7 +33,7 @@
                 Value="1"
                 KeyPath="yes"/>
         </Component>
-    </Directory>
+    </StandardDirectory>
 		<StandardDirectory Id="ProgramFiles6432Folder">
 			<Directory Id="INSTALLFOLDER" Name="CCExtractor">
 				<Directory Id="CCX_data" Name="data">