Check that when the client sends an arbitrary later version, the server
response with its latest supported version.

-- client --
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "2029-01-01",
    "capabilities": {},
    "clientInfo": { "name": "ExampleClient", "version": "1.0.0" }
  }
}
-- server --
{
	"jsonrpc": "2.0",
	"id": 1,
	"result": {
		"capabilities": {
			"logging": {}
		},
		"protocolVersion": "2025-06-18",
		"serverInfo": {
			"name": "testServer",
			"version": "v1.0.0"
		}
	}
}
