feat: enhance contact group management with uid normalization and improved member handling

locales/en/common.json

@@ -1230,6 +1230,7 @@
     "empty_search_hint": "Try a different search term",
     "clear_search": "Clear search",
     "import_vcard": "Import vCard",
+    "delete_confirm_title": "Delete contact",
     "delete_confirm": "Are you sure you want to delete this contact?",
     "local_mode": "Contacts are stored locally (server does not support JMAP Contacts)",
     "back_to_mail": "Back to mail",
@@ -1376,6 +1377,7 @@
       "create": "New Group",
       "edit": "Edit Group",
       "empty": "No groups yet",
+      "delete_confirm_title": "Delete group",
       "delete_confirm": "Are you sure you want to delete this group?",
       "name_label": "Group Name",
       "name_placeholder": "e.g., Team, Family",
@@ -1412,6 +1414,7 @@
       "selected": "{count, plural, one {1 selected} other {# selected}}",
       "select_all": "Select all",
       "delete": "Delete",
+      "delete_confirm_title": "Delete contacts",
       "delete_confirm": "Delete {count, plural, one {1 contact} other {# contacts}}?",
       "deleted": "{count, plural, one {1 contact deleted} other {# contacts deleted}}",
       "add_to_group": "Add to group",