Build the MSI with cimipkg instead of WiX

[rodchristiansen]

This PR stays a draft until a choice is made: move the MSI to cimipkg (this PR), or first fix the WiX build's UpgradeCode.

Why

Every WiX-built release gets a random UpgradeCode, because .wix-upgrade-code is never committed and CI generates a new one each time. There is no MajorUpgrade either, so each release installs alongside the previous ones instead of replacing them. For example, v2026.10.07.1517 has {F93C3305-…} and v2026.10.07.1403 has {7FC5FA55-…}.

What changed

• build.ps1 -Msi uses cimipkg. It stages the publish output, scripts/ and build-info.yaml (with ${TIMESTAMP} and architecture filled in), then runs cimipkg. cimipkg is found in tools\ (gitignored) or on PATH. cimipkg derives a stable UpgradeCode from the identifier ({0e959fd4-b21a-53e2-bc69-23eada0614ce}) and supersedes older builds. All the WiX authoring code is removed.
• No new install logic. scripts/postinstall.ps1 already handled the PATH entry, the Start menu shortcut and the ManagedNotifications ACLs. scripts/uninstall.ps1 already removes the shortcut and PATH entry.
• Release workflow. release.yml downloads cimipkg instead of installing WiX.
• Cleanup script. deploy/Remove-WixCsharpDialog.ps1 uninstalls the side-by-side WiX installs, matching DisplayName csharpDialog and Publisher windowsadmins. cimipkg builds are never touched, because their publisher is Windows Admins Open Source. Run it before the first cimipkg release lands: a WiX uninstall removes the files, PATH entry and shortcut that the cimipkg package also uses. sbin-installer already removes same-name products before it installs, in that order.

Tested

• Build. build.ps1 -Build -Msi on a Windows 11 x64 build host produced csharpdialog-x64 and csharpdialog-arm64 MSIs through cimipkg.
  • Both carry UpgradeCode {0e959fd4-b21a-53e2-bc69-23eada0614ce} and version 26.10.801.
  • The x64 MSI holds 762 files plus the pre-, post- and uninstall scripts.
• Install in Windows Sandbox (Windows 11 26100, msiexec as SYSTEM). This used an MSI from the VBScript-free cimipkg (cimian-pkg#51), because Sandbox has no VBScript:

Step	Exit	ARP	PATH entry	Start menu shortcut	dialog.exe	ManagedNotifications DACL
WiX release v2026.10.07.1517 installed	0	26.10.7.1517 / windowsadmins	yes	yes	yes	D:P(A;OICI;FA;;;SY)(A;OICI;FA;;;BA)(A;OICI;0x1200a9;;;BU)
Remove-WixCsharpDialog.ps1	0	none	no	no	no	unchanged (folder is kept)
cimipkg build installed	0	26.10.801 / Windows Admins Open Source	yes	yes	yes	D:PAI(A;OICI;FA;;;SY)(A;OICI;FA;;;BA)(A;OICI;0x1200a9;;;BU)
cimipkg build uninstalled	0	none	no	no	no	kept
WiX release reinstalled, then sbin-installer installs the cimipkg build	0	26.10.801 only; the WiX product was removed by name	yes	yes	yes	D:PAI…

• The one difference. The WiX MSI wrote the ManagedNotifications DACL as D:P, and postinstall.ps1 writes it as D:PAI. The ACEs are identical, and both are protected (no inheritance from ProgramData). AI only marks the DACL as auto-inherited for propagation to children.

Not tested

• A machine holding several side-by-side WiX installs. Only one WiX release MSI was available. The cleanup script loops over every match.
• arm64. No device is available here.
• The release workflow. It was not run.