NSIS silent install with `selectPerMachineByDefault: true` skips UAC on fresh install

[gzdunek]

• Electron-Builder Version: 26.8.2
• Node Version: 24.14.0
• Electron Version: 40.1.0
• Target: NSIS

When using NSIS multi-user mode (oneClick: false) with selectPerMachineByDefault: true, a fresh silent install (/S) does not trigger UAC and fails due to insufficient privileges.

Running the silent installation from an administrator console works correctly.

To Reproduce

1. Configure NSIS:
   • oneClick: false
   • perMachine: false
   • selectPerMachineByDefault: true
2. Run fresh install as non-admin:
   • MyAppSetup.exe /S
3. The app is not installed, no error is displayed.

Suspected root cause

In packages/app-builder-lib/templates/nsis/installer.nsi, UAC in silent mode is triggered only when there is a previous per-machine installation, the resolved mode is ignored:

electron-builder/packages/app-builder-lib/templates/nsis/installer.nsi

Lines 101 to 102 in ed422f3

	${if} $hasPerMachineInstallation == "1" # set in onInit by initMultiUser
	${andIf} ${Silent}

Proposed fix

Broaden condition to include resolved per-machine mode:

${if} $hasPerMachineInstallation == "1" # set in onInit by initMultiUser 
${OrIf} $installMode == "all"
${andIf} ${Silent}