- list_generated_keys now fetches live keys from upstream API, merges with
local DB: remote keys with plaintext values are auto-upserted (by
group_id+managed_prefix), remote-only keys shown as unimportable
- Use _fetch_remote_managed_prefixes to support custom key prefixes
- Group remote keys by (group_id, prefix), pick latest by key_id
- Extract _remote_group_name helper for safe group name parsing
(handles dict group field from Meow upstream)
- Frontend excludes orphaned keys from importable list
- Backend import endpoint reconciles upstream before importing