[Client] cleanup leftover dns and nrpt policies on windows

[Exobitt]

Describe your changes

In some cases, the Windows client does not clean up DNS and NRPT policies in the registry.
This can break the user's DNS resolution when using split-horizon DNS.
If these entries are not properly removed, the user may lose access to domains configured under the split-horizon setup.

Issue ticket number and link

N/A

Stack

Windows

Checklist

• Is it a bug fix
• Is a typo/documentation fix
• Is a feature enhancement
• It is a refactor
• Created tests that fail without the change (if possible)

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Documentation

Select exactly one:

• I added/updated documentation for this change
• Documentation is not needed for this change (explain why)
  It happens in the uninstaller

Docs PR URL (required if "docs added" is checked)

Paste the PR link from https://github.com/netbirdio/docs here:

https://github.com/netbirdio/docs/pull/__

[CLAassistant]

All committers have signed the CLA.

[Copilot]

Pull Request Overview

This PR addresses a bug where the Windows client fails to clean up DNS and NRPT (Name Resolution Policy Table) policies from the registry during uninstallation, which can break DNS resolution for users with split-horizon DNS configurations.

• Adds PowerShell script execution during uninstallation to remove Netbird-related DNS policy registry entries
• Implements registry cleanup with error handling and service restart
• Ensures proper cleanup of NRPT entries to prevent DNS resolution issues after uninstallation

Comments suppressed due to low confidence (3)

client/installer.nsis:1

• [nitpick] The regex pattern uses 'netbird' (lowercase) but the comment and description reference 'Netbird' (capitalized). Consider using a case-insensitive match that explicitly matches the actual product name, such as '^(?i)netbird' or clarifying the expected naming convention in the registry keys.

!define APP_NAME "Netbird"

client/installer.nsis:1

• The Write-Host cmdlets with -ForegroundColor may not display properly in the NSIS installer context since the PowerShell is executed with -WindowStyle Hidden. Consider removing the color parameters or using Write-Output for better compatibility with the installer's logging mechanism.

!define APP_NAME "Netbird"

client/installer.nsis:1

• The Write-Host cmdlets with -ForegroundColor may not display properly in the NSIS installer context since the PowerShell is executed with -WindowStyle Hidden. Consider removing the color parameters or using Write-Output for better compatibility with the installer's logging mechanism.

!define APP_NAME "Netbird"

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[lixmal]

Hi @Exobitt, thank you for the contribution.

Is this required?

For context: the client cleans up the registry on shutdown. Or in case of a crash, on startup, based on the state file.

The only two scenarios where this is a problem are:

• The state file becomes corrupted for some reason
• NetBird is uninstalled after a crash and doesn't get the chance to clean up
  The registry entries are volatile, so a reboot will also clean them up.