Hide existing new (remake)

[cgaarden]

Summary of the Pull Request

• Add the ability for users and admins (GPO) to control whether to display built in New on the context menu.
• Changes to the setting are immediately reflected in the experience.
• Built-in New is restored on uninstall.

PR Checklist

Note: Supersedes #39843

• Closes: [New+] Replace default New entry [New+] Replace default New entry #37545 and Replace "New" with New+ option Replace "New" with New+ option #37946
• Communication: Discussed with @niels9001 - 1/22/2025
• Tests: Completed manual test pass see highlight below
• Localization: All end-user-facing strings can be localized
• Dev docs: Updated "doc\devdocs\modules\newplus.md"
• [n/a] New binaries: Added on the required places
  • [n/a] JSON for signing for new binaries
  • [WXS for installer] Updated installer (uninstall custom action)
  • [n/a] YML for CI pipeline for new test projects
  • [n/a] YML for signed pipeline
• [No] Documentation updated: Pending, coming soon. (original PR
  New+ Feature - Doc Update - Option to hide the built-in New context m… MicrosoftDocs/windows-dev-docs#5473)

Detailed Description of the Pull Request / Additional comments

Added the ability for users' admins' to display Windows built-in New or not

I'm NOT aware of an official supported way to do this, so I'm achieving this by adding an invalid context menu handler in place of New in the Computer\HKEY_CURRENT_USER\Software\Classes\Directory\background\ShellEx\ContextMenuHandlers\New

Changes are immediate, after applying the change, built-in New is shown/hidden accordingly

Updates to New+ Settings UI
	New setting introduced to track user' preference (saved to newplus/settings.json) 
	GPO setting introduced for control New visibility via GPO (GPO wins over user preference)

Updates to New+ power_module.cpp
	When runner is running new plus will also apply built-in New admin GPO and user preference (GPO wins over user preference) to ensure correct behavior on setting restore and GPO application.
	
Updates to installer 
	Uninstall always reenable built-in "New" context menu 

Updated DevDoc
	Added a note on how to manually restore built-in New

Validation Steps Performed

Windows 11 x64
Settings UI
New+ enabled
New+ disabled
GPO setting enabled
GPO settings disabled
Manually updating newplus/settings.json

Windows 11 ARM64
I tested the reg hack manually, but didn't go through a full pass.

Windows 10 x64
NOT tested.

Windows 11, Settings, New+ Disabled and no GPO

Windows 11, Settings, New+ Enabled and no GPO

Hide built-in New: Off (the default)

Hide built-in New: On

Modern

Classic

Disabling New+ also unhide New

Windows 11, Settings, New+ Enabled and with GPO

Hide built-in New: GPO enabled

Hide built-in New: GPO disabled

[cgaarden]

Hi @niels9001 -- as discussed here's the initial PR. Thanks again!