cli: stop doubling the scheme on a remote CLI address

newRemoteClient prepended "https://" unconditionally, so
HEADSCALE_CLI_ADDRESS=https://host became https://https://host and dialed
the host "https". Default a bare host to https, keep an explicit scheme.

cmd/headscale/cli/utils.go

@@ -241,6 +241,18 @@ func dialHeadscaleSocket(ctx context.Context, socketPath string) (net.Conn, erro
 	}, backoff.WithBackOff(b))
 }
 
+// clientBaseURL turns a configured CLI address into a client base URL. A bare
+// host[:port] (the historical form) defaults to https; an address that already
+// carries a scheme is used as-is, so an explicit http:// or https:// is honoured
+// rather than doubled into https://https://...
+func clientBaseURL(address string) string {
+	if strings.Contains(address, "://") {
+		return address
+	}
+
+	return "https://" + address
+}
+
 // newRemoteClient builds an API client for a remote Headscale over HTTPS,
 // honouring insecure (skip TLS verification) and injecting the API key as a
 // bearer token on every request.
@@ -257,7 +269,7 @@ func newRemoteClient(address, apiKey string, insecure bool) (*clientv1.ClientWit
 	httpClient := &http.Client{Transport: transport}
 
 	return clientv1.NewClientWithResponses(
-		"https://"+address,
+		clientBaseURL(address),
 		clientv1.WithHTTPClient(httpClient),
 		clientv1.WithRequestEditorFn(func(_ context.Context, req *http.Request) error {
 			req.Header.Set("Authorization", "Bearer "+apiKey)

cmd/headscale/cli/utils_test.go

@@ -0,0 +1,35 @@
+package cli
+
+import "testing"
+
+func TestClientBaseURL(t *testing.T) {
+	tests := []struct {
+		name    string
+		address string
+		want    string
+	}{
+		{
+			name:    "bare host defaults to https",
+			address: "headscale.example.com:50443",
+			want:    "https://headscale.example.com:50443",
+		},
+		{
+			name:    "explicit https scheme is kept",
+			address: "https://headscale.example.com",
+			want:    "https://headscale.example.com",
+		},
+		{
+			name:    "explicit http scheme is kept",
+			address: "http://localhost:8080",
+			want:    "http://localhost:8080",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := clientBaseURL(tt.address); got != tt.want {
+				t.Errorf("clientBaseURL(%q) = %q, want %q", tt.address, got, tt.want)
+			}
+		})
+	}
+}