Add parameters check for adding Runtime Host.

### Problem

When we add a Runtime Host, we don't know whether we sign legal parameters for setting, and there's no a buttom like Test Connection or Save But Not Enable. Also it seems not be able to be updated? When saving, the app will test connection and not meaningful reason for fail anymore. It is so confusing.

### Desired outcome

Yes, I can see the whether the parameters I've signed are legal. And it's so good if I can make testing connection and update a saved setting. Also it will be better if I get the detailed for why the connectiong is failed.

### Alternatives or workarounds

_No response_

Start by locating the Runtime Host add/save flow and its connection test or validation handling in the desktop app. Trace how saved settings are updated and how connection failures are reported; done should include parameter validation, an explicit connection test or save-without-enabling path, updating saved settings, and useful failure details.

Written by the indexing model from the issue text.