refactor: unify agent communication with Transport interface

- Introduce `Transport` interface to abstract WebSocket and SSH
communication
- Add generic `Data` field to `AgentResponse` for streamlined future
endpoints
- Maintain backward compatibility with legacy hubs and agents using
typed fields
- Unify fetch operations (SMART, systemd, containers) under a single
`request` method
- Improve `RequestManager` with deadline awareness and legacy response
support
- Refactor agent response routing into dedicated `agent/response.go`
- Update version to 0.18.0-beta.2

internal/hub/ws/ws_test.go

@@ -184,14 +184,18 @@ func TestCommonActions(t *testing.T) {
 	assert.Equal(t, common.WebSocketAction(2), common.GetContainerLogs, "GetLogs should be action 2")
 }
 
-func TestLogsHandler(t *testing.T) {
-	h := &stringResponseHandler{errorMsg: "no logs in response"}
+func TestFingerprintHandler(t *testing.T) {
+	var result common.FingerprintResponse
+	h := &fingerprintHandler{result: &result}
 
-	logValue := "test logs"
-	resp := common.AgentResponse{String: &logValue}
+	resp := common.AgentResponse{Fingerprint: &common.FingerprintResponse{
+		Fingerprint: "test-fingerprint",
+		Hostname:    "test-host",
+	}}
 	err := h.Handle(resp)
 	assert.NoError(t, err)
-	assert.Equal(t, logValue, h.value)
+	assert.Equal(t, "test-fingerprint", result.Fingerprint)
+	assert.Equal(t, "test-host", result.Hostname)
 }
 
 // TestHandler tests that we can create a Handler