fix(marge): delete stored groups on account teardown

HandleMargeDeleteAccountGroups (DELETE /streaming/account/{id}/group/,
no group ID) had become a pure acknowledgement, leaving
DeleteAllGroupsForAccount dead code. This is the exact request real
firmware sends on factory reset/teardown; skipping the delete leaves a
stale Group_*.xml behind, permanently rejecting the next legitimate
Create for those devices via EnsureNoGroupsForDevices with no operator
remedy.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

pkg/service/handlers/handlers_marge.go

@@ -965,10 +965,10 @@ func (s *Server) HandleMargeDeleteGroup(w http.ResponseWriter, r *http.Request)
 	_, _ = w.Write([]byte(constants.XMLHeader + `<status>Group deleted successfully</status>`))
 }
 
-// HandleMargeDeleteAccountGroups acknowledges legacy speaker teardown
-// callbacks that carry no group ID. Such a request cannot identify a group
-// generation safely, so it is deliberately non-mutating. Generation-aware
-// callers use HandleMargeDeleteGroup instead.
+// HandleMargeDeleteAccountGroups handles legacy speaker teardown callbacks
+// that carry no group ID (e.g. factory reset). It deletes every stored group
+// for the account, mirroring the real firmware expectation that this call
+// clears all group state so a later Create isn't blocked by a stale record.
 func (s *Server) HandleMargeDeleteAccountGroups(w http.ResponseWriter, r *http.Request) {
 	account := chi.URLParam(r, "account")
 
@@ -977,6 +977,11 @@ func (s *Server) HandleMargeDeleteAccountGroups(w http.ResponseWriter, r *http.R
 		return
 	}
 
+	if err := s.ds.DeleteAllGroupsForAccount(account); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
 	w.Header().Set("Content-Type", "application/vnd.bose.streaming-v1.2+xml")
 	w.WriteHeader(http.StatusOK)
 	_, _ = w.Write([]byte(constants.XMLHeader + `<status>Group teardown acknowledged</status>`))

pkg/service/handlers/handlers_marge_group_lifecycle_test.go

@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"encoding/xml"
+	"errors"
 	"fmt"
 	"net/http"
 	"net/http/httptest"
@@ -210,24 +211,34 @@ func TestMargeDeviceGroupReturns500ForMalformedOrUnreadableData(t *testing.T) {
 	}
 }
 
-func TestMargeDeleteAccountGroupsAcknowledgesWithoutDeleting(t *testing.T) {
+func TestMargeDeleteAccountGroupsDeletesAllGroupsForAccount(t *testing.T) {
 	ds := datastore.NewDataStore(t.TempDir())
 	handler := margeLifecycleRouter(ds)
 	const account = "ACCOUNT1"
+	const otherAccount = "ACCOUNT2"
 
 	group := margeLifecycleGroup("MASTER", "MASTER", "SLAVE", "Current pair")
 	if _, err := ds.AddGroup(account, &group); err != nil {
 		t.Fatalf("add group: %v", err)
 	}
 
+	otherGroup := margeLifecycleGroup("OTHER-MASTER", "OTHER-MASTER", "OTHER-SLAVE", "Other account pair")
+	if _, err := ds.AddGroup(otherAccount, &otherGroup); err != nil {
+		t.Fatalf("add group in other account: %v", err)
+	}
+
 	response := margeLifecycleRequest(t, handler, http.MethodDelete,
 		"/streaming/account/"+account+"/group/", "192.0.2.10:1234", "")
 	if response.Code != http.StatusOK {
 		t.Fatalf("DELETE status = %d, want 200; body=%s", response.Code, response.Body.String())
 	}
 
-	if current, err := ds.GetGroupForDevice(account, "MASTER"); err != nil || current.ID != group.ID {
-		t.Fatalf("generation-less teardown changed stored group: group=%#v err=%v", current, err)
+	if _, err := ds.GetGroupForDevice(account, "MASTER"); !errors.Is(err, datastore.ErrGroupNotFound) {
+		t.Fatalf("generation-less teardown did not delete stored group: err=%v", err)
+	}
+
+	if current, err := ds.GetGroupForDevice(otherAccount, "OTHER-MASTER"); err != nil || current.ID != otherGroup.ID {
+		t.Fatalf("teardown affected a different account's group: group=%#v err=%v", current, err)
 	}
 }