[BUG] Devolutions Agent broker not detected by UniGetUI 2026.2.7

### Please confirm these before moving forward

- [x] I have searched for my issue and have not found a work-in-progress/duplicate/resolved issue.
- [x] I have tested that this issue has not been fixed in the latest [(beta or stable) release](https://github.com/Devolutions/UniGetUI/releases/).
- [x] I have checked the [FAQ](https://github.com/Devolutions/UniGetUI#frequently-asked-questions) section for solutions.
- [x] This issue is about a bug (if it is not, please use the [correct template](https://github.com/Devolutions/UniGetUI/issues/new/choose)).

### UniGetUI Version

2026.2.7

### Windows version, edition, and architecture

Windows 10/11 (multiple editions) x64

### Describe your issue

I have installed Devolutions Agent and enabled "Use Agent Broker" in UniGetUI.

Environment:
- Windows
- UniGetUI 2026.2.7 (Microsoft Store)
- Devolutions Agent 2026.2.3.0
- Agent service is running as LocalSystem (NT Authority\System)

The Agent service is running normally:

Service: DevolutionsAgent
State: Running
PID: 6432 (at that thime)
Path: C:\Program Files\Devolutions\Agent\DevolutionsAgent.exe

However, when UniGetUI tries to perform an update, it reports:

Routing operation through Devolutions Agent broker...
Agent broker is not available. The operation cannot continue.
The Devolutions Agent broker is not available. The operation cannot be performed.
Please ensure the Devolutions Agent is installed and running.

The Devolutions Agent log only contains the service startup/shutdown messages and shows no request from UniGetUI when the broker error occurs.

I also checked the running processes, listening TCP connections and handles of both UniGetUI and DevolutionsAgent. No obvious broker endpoint/pipe could be identified.

The UniGetUI configuration contains the empty marker file:

%LOCALAPPDATA%\UniGetUI\Configuration\UseAgentBroker

The Agent is installed through WinGet. However, the current WinGet package for Devolutions.Agent only provides version 2026.2.3.0, so `winget upgrade --id Devolutions.Agent` simply reinstalls the same version.

Is Devolutions Agent 2026.2.3.0 compatible with the Agent Broker used by UniGetUI 2026.2.7, or is a newer Agent version required?
If a newer version is required, when/how will it become available through the official WinGet package?

### Steps to reproduce the issue

Install UniGetUI
Install Devolutions Agent
Active use of agent
Try to update a package

### UniGetUI Log

```text
No information found about agent or broker, not even warnings, errors or fails!?
```

### Package Managers Logs

```text
Not relevant
```

### Relevant information

See description

### Screenshots and videos

_No response_

Start by reproducing the update flow with UniGetUI 2026.2.7, Devolutions Agent 2026.2.3.0, and the UseAgentBroker marker at %LOCALAPPDATA%\UniGetUI\Configuration\UseAgentBroker. Check the UniGetUI and Devolutions Agent logs while the broker error occurs; done means the compatibility requirement or failure cause is established and the required Agent or WinGet package version is identified.

Written by the indexing model from the issue text.