feat(ui): open list items counter on Listen, none on Workspace

New stat listItemsOpenCount: unchecked items in all lists the user sees
(own, shared directly or through a group), shown as accent counter on
Listen in the header and the mobile bottom bar. Workspace loses its
counter. Stats refresh on list events and after deleting an item.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/storage/system_test.go

@@ -0,0 +1,49 @@
+package storage
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+func TestOpenListItemsCountCoversSharedLists(t *testing.T) {
+	store, err := NewStore(filepath.Join(t.TempDir(), "stats.db"))
+	if err != nil {
+		t.Fatalf("NewStore: %v", err)
+	}
+	defer store.Close()
+	openSharing(t, store)
+	anna, _ := store.CreateUser("anna@example.com", "hash", "Anna", "member")
+	ben, _ := store.CreateUser("ben@example.com", "hash", "Ben", "member")
+	carla, _ := store.CreateUser("carla@example.com", "hash", "Carla", "member")
+
+	addItems := func(owner, listID string, open, done int) {
+		for i := 0; i < open+done; i++ {
+			item, _ := store.CreateListItem(listID, "Eintrag", "", "", i, owner)
+			if i >= open {
+				_, _ = store.ToggleListItem(item.ID, true, owner, "")
+			}
+		}
+	}
+	own, _ := store.CreateList(anna.ID, "Einkauf", "🛒", "shopping")
+	addItems(anna.ID, own.ID, 2, 1)
+	direct, _ := store.CreateList(ben.ID, "Bens Liste", "", "shopping")
+	addItems(ben.ID, direct.ID, 1, 2)
+	if _, err := store.AddListShare(ben.ID, direct.ID, "user", anna.ID, "viewer"); err != nil {
+		t.Fatalf("share: %v", err)
+	}
+	viaGroup, _ := store.CreateList(carla.ID, "WG-Putzplan", "", "shopping")
+	addItems(carla.ID, viaGroup.ID, 3, 0)
+	team, _ := store.CreateTeam("", "WG", "")
+	_ = store.AddTeamMember(team.ID, anna.ID, "member")
+	_ = store.AddTeamMember(team.ID, carla.ID, "admin")
+	if _, err := store.AddListShare(carla.ID, viaGroup.ID, "team", team.ID, "editor"); err != nil {
+		t.Fatalf("team share: %v", err)
+	}
+	foreign, _ := store.CreateList(ben.ID, "Privat", "", "shopping")
+	addItems(ben.ID, foreign.ID, 5, 0)
+
+	st, _ := store.GetDashboardStats(anna.ID)
+	if st.ListItemsOpenCount != 6 || st.ListsCount != 3 {
+		t.Errorf("want 6 open items in 3 lists (own 2 + direct 1 + group 3), got %d in %d", st.ListItemsOpenCount, st.ListsCount)
+	}
+}