Let the instance service account list a team's deadman switches

GET /api/teams/{id}/deadman/switches used requireTeamMember, which 404s
for the instance-scoped service account because it belongs to no team.
terdut-operator lists switches by name on every reconcile, so TerdutTeams
never became ready. Instance service accounts now pass, as they already do
for the write endpoints.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

charts/terdut-server/Chart.yaml

@@ -15,5 +15,5 @@ type: application
 # appVersion and image.tag in values.yaml no longer agree, and that is not an oversight:
 # image.tag stays "latest", which is what a local install actually pulls. appVersion is
 # metadata and drives nothing.
-version: 0.47.1
-appVersion: "v0.47.1"
+version: 0.47.2
+appVersion: "v0.47.2"

internal/api/service_accounts_test.go

@@ -490,3 +490,31 @@ func TestDeadman_UpdateInPlacePreservesID(t *testing.T) {
 		t.Errorf("expected the update to replace in place, not add a row, got %d switches", len(list))
 	}
 }
+
+// The operator reconciles a team's dead man's switches by listing them, and its
+// instance-scoped account is not a member of any team it manages.
+func TestServiceAccount_InstanceScopeListsATeamsDeadmanSwitches(t *testing.T) {
+	s := newTS(t)
+	instanceKey := createServiceAccount(t, s, s.key, "terdut-operator", models.ServiceAccountScopeInstance, 0)
+	team := createTeamAs(t, s, instanceKey, "team-a")
+	path := "/api/teams/" + id64(team) + "/deadman/switches"
+
+	resp := s.reqAs(t, instanceKey, http.MethodPost, path,
+		map[string]any{"name": "watchdog", "matcher": "alertname=Watchdog", "timeout_seconds": 900, "severity": "critical"})
+	if resp.StatusCode != http.StatusCreated {
+		t.Fatalf("create switch: %d", resp.StatusCode)
+	}
+	resp.Body.Close()
+
+	resp = s.reqAs(t, instanceKey, http.MethodGet, path, nil)
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("list switches as the instance account: %d", resp.StatusCode)
+	}
+	var list []struct {
+		Name string `json:"name"`
+	}
+	decode(t, resp, &list)
+	if len(list) != 1 || list[0].Name != "watchdog" {
+		t.Errorf("expected the one switch just created, got %+v", list)
+	}
+}

internal/api/teams.go

@@ -826,7 +826,10 @@ func handleListTeamDeadman(db *sql.DB) http.HandlerFunc {
 		if !ok {
 			return
 		}
-		if !requireTeamMember(w, r, teamID) {
+		// The operator's instance-scoped account reconciles the switches by name,
+		// so it has to read them without being a member: that is owner reach,
+		// the same as the writes below, and still reads no incidents.
+		if !isInstanceServiceAccount(r.Context()) && !requireTeamMember(w, r, teamID) {
 			return
 		}