Fix PBS discovery causing auth failures

Increases confidence score for PBS when receiving 401/403 responses to avoid unnecessary probing of other endpoints that trigger auth failure logs.

Fixes #741

pkg/discovery/discovery.go

@@ -51,13 +51,13 @@ type DiscoveryResult struct {
 // friendlyPhaseName converts technical phase names to user-friendly descriptions
 func friendlyPhaseName(phase string) string {
 	friendlyNames := map[string]string{
-		"lxc_container_network":      "Container network",
+		"lxc_container_network":    "Container network",
-		"docker_bridge_network":      "Docker bridge network",
+		"docker_bridge_network":    "Docker bridge network",
-		"docker_container_network":   "Docker container network",
+		"docker_container_network": "Docker container network",
-		"host_local_network":         "Local network",
+		"host_local_network":       "Local network",
-		"inferred_gateway_network":   "Gateway network",
+		"inferred_gateway_network": "Gateway network",
-		"extra_targets":              "Additional targets",
+		"extra_targets":            "Additional targets",
-		"proxmox_cluster_network":    "Proxmox cluster network",
+		"proxmox_cluster_network":  "Proxmox cluster network",
 	}
 
 	if friendly, ok := friendlyNames[phase]; ok {
@@ -1193,9 +1193,12 @@ func (s *Scanner) applyPBSHeuristics(ctx context.Context, address string, result
 		}
 	case http.StatusUnauthorized, http.StatusForbidden:
 		if versionFinding.ProductGuess == productPBS {
-			result.addConfidence(productPBS, "auth headers indicated PBS", 0.45, true)
+			result.addConfidence(productPBS, "auth headers indicated PBS", 0.55, true)
 		} else {
-			result.addConfidence(productPBS, "version endpoint on PBS port requires auth", 0.35, true)
+			// High confidence: Port 8007 + api2/json/version exists (even if auth required) is a very strong signal.
+			// We bump this to ensure we cross the threshold and avoid probing other endpoints (status/datastore)
+			// which would generate "authentication failure" logs on the server.
+			result.addConfidence(productPBS, "version endpoint on PBS port requires auth", 0.55, true)
 		}
 	default:
 		if result.Reachable && result.ProductScores[productPBS] < 0.25 {

pkg/discovery/discovery_test.go

@@ -427,3 +427,41 @@ func TestDiscoverServersCancelledContext(t *testing.T) {
 		t.Fatalf("expected no servers on cancelled context")
 	}
 }
+
+func TestPBSDiscoveryWithUnauthorizedVersion(t *testing.T) {
+	// Handler that simulates PBS requiring auth for version endpoint
+	// and NOT providing any helpful headers initially to test the port+auth heuristic
+	pbsHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/api2/json/version" {
+			w.WriteHeader(http.StatusUnauthorized)
+			return
+		}
+		http.NotFound(w, r)
+	})
+
+	server := startTLSServerOn(t, "127.0.0.1:8007", pbsHandler)
+	_ = server
+
+	scanner := newTestScanner(&http.Client{
+		Timeout:   500 * time.Millisecond,
+		Transport: &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: true}},
+	})
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+
+	// Probe port 8007
+	probe := scanner.ProbeProxmoxService(ctx, "127.0.0.1", 8007)
+
+	if probe == nil {
+		t.Fatal("ProbeProxmoxService returned nil")
+	}
+
+	if !probe.Positive {
+		t.Errorf("Expected positive identification for PBS on port 8007 with 401 version response, got negative. Score: %f", probe.PrimaryScore)
+	}
+
+	if probe.PrimaryProduct != ProductPBS {
+		t.Errorf("Expected product %q, got %q", ProductPBS, probe.PrimaryProduct)
+	}
+}