Stop macOS agent updates from spawning BTM entries

Unsigned darwin release tarballs replaced the Developer ID
binary on each auto-update, so Background Task Management
treated every release as a new identity and showed the generic
executable icon. Sign those archives with a stable identifier,
refuse signature downgrades, and attribute daemon/tray jobs to
Probo Agent.app via AssociatedBundleIdentifiers.

Signed-off-by: Ludovic Vielle <ludovic@probo.com>

pkg/deviceagent/update/install_signature_identity_test.go

@@ -0,0 +1,171 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+package update
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestParseCodeSigningIdentity(t *testing.T) {
+	t.Parallel()
+
+	cases := []struct {
+		name string
+		out  string
+		want codeSigningIdentity
+	}{
+		{
+			name: "developer id signed binary",
+			out: "" +
+				"Executable=/usr/local/bin/probo-agent\n" +
+				"Identifier=com.probo.agent\n" +
+				"Format=Mach-O thin (arm64)\n" +
+				"TeamIdentifier=ABCD123456\n",
+			want: codeSigningIdentity{
+				Team:       "ABCD123456",
+				Identifier: "com.probo.agent",
+			},
+		},
+		{
+			name: "team identifier not set",
+			out: "" +
+				"Identifier=probo-agent\n" +
+				"Signature=adhoc\n" +
+				"TeamIdentifier=not set\n",
+			want: codeSigningIdentity{
+				Team:       "",
+				Identifier: "probo-agent",
+			},
+		},
+		{
+			name: "unsigned output has empty fields",
+			out:  "code object is not signed at all\n",
+			want: codeSigningIdentity{},
+		},
+		{
+			name: "empty identifier value",
+			out: "" +
+				"Identifier=\n" +
+				"TeamIdentifier=ABCD123456\n",
+			want: codeSigningIdentity{
+				Team:       "ABCD123456",
+				Identifier: "",
+			},
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(
+			tc.name,
+			func(t *testing.T) {
+				t.Parallel()
+
+				got := parseCodeSigningIdentity(tc.out)
+				assert.Equal(t, tc.want, got)
+			},
+		)
+	}
+}
+
+func TestCodeSigningIdentitiesCompatible(t *testing.T) {
+	t.Parallel()
+
+	stable := codeSigningIdentity{
+		Team:       "ABCD123456",
+		Identifier: "com.probo.agent",
+	}
+
+	cases := []struct {
+		name      string
+		current   codeSigningIdentity
+		candidate codeSigningIdentity
+		wantErr   string
+	}{
+		{
+			name:    "allows unsigned to signed upgrade",
+			current: codeSigningIdentity{},
+			candidate: codeSigningIdentity{
+				Team:       "ABCD123456",
+				Identifier: "com.probo.agent",
+			},
+		},
+		{
+			name:      "allows matching team and identifier",
+			current:   stable,
+			candidate: stable,
+		},
+		{
+			name:    "refuses signed to unsigned downgrade",
+			current: stable,
+			candidate: codeSigningIdentity{
+				Identifier: "com.probo.agent",
+			},
+			wantErr: "refusing signature downgrade",
+		},
+		{
+			name:    "refuses team mismatch",
+			current: stable,
+			candidate: codeSigningIdentity{
+				Team:       "OTHERTEAM1",
+				Identifier: "com.probo.agent",
+			},
+			wantErr: "does not match current Team ID",
+		},
+		{
+			name:    "refuses same team with different identifier",
+			current: stable,
+			candidate: codeSigningIdentity{
+				Team:       "ABCD123456",
+				Identifier: "com.probo.agent.other",
+			},
+			wantErr: "does not match current Identifier",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(
+			tc.name,
+			func(t *testing.T) {
+				t.Parallel()
+
+				err := codeSigningIdentitiesCompatible(tc.current, tc.candidate)
+				if tc.wantErr == "" {
+					assert.NoError(t, err)
+					return
+				}
+
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), tc.wantErr)
+			},
+		)
+	}
+}
+
+func TestIsUnsignedCodesignOutput(t *testing.T) {
+	t.Parallel()
+
+	assert.True(t, isUnsignedCodesignOutput("code object is not signed at all"))
+	assert.True(t, isUnsignedCodesignOutput("TeamIdentifier=not set\n"))
+	assert.False(t, isUnsignedCodesignOutput("TeamIdentifier=ABCD123456\n"))
+}