fix(bitdefender): fifth-pass - companies lists full fleet, drop unused import

Convergence-pass LOW/NIT cleanup:
- cmd_companies uses list_all_companies() so a >100-company tenant isn't truncated
  in the listing (was page-1 only); matches sweep/inventory.
- removed unused 'field' import from dataclasses.
Deliberately NOT changed: id validation on delete-package/report-delete/blocklist-
remove/quarantine-remove/restore - those ids are not pinned 24-hex format, so
validating could reject valid input; they are --confirm-gated and bad ids match
the expected-error markers (no mislog). 81/81 selftest.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.claude/skills/bitdefender/scripts/gz_client.py

@@ -31,7 +31,7 @@ import time
 import urllib.error
 import urllib.request
 from contextlib import contextmanager
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from datetime import datetime, timezone
 from email.utils import parsedate_to_datetime
 from pathlib import Path