## Summary

This PR is a follow-up from #19551
and adds a new `ty.experimental.rename` setting to conditionally
register for the rename capability. The complementary PR in ty VS Code
extension is astral-sh/ty-vscode#111.

This is done using dynamic registration after the settings have been
resolved. The experimental group is part of the global settings because
they're applied for all workspaces that are managed by the client.

## Test Plan

Add E2E tests.

In VS Code, with the following setting:
```json
{
	"ty.experimental.rename": "true",
	"python.languageServer": "None"
}
```

I get the relevant log entry:
```
2025-08-07 16:05:40.598709000 DEBUG client_response{id=3 method="client/registerCapability"}: Registered rename capability
```

And, I'm able to rename a symbol. Once I set it to `false`, then I can
see this log entry:

```
2025-08-07 16:08:39.027876000 DEBUG Rename capability is disabled in the client settings
```

And, I don't see the "Rename Symbol" open in the VS Code dropdown.


https://github.com/user-attachments/assets/501659df-ba96-4252-bf51-6f22acb4920b