GHSA-WWV5-G3V4-889X Tornado: Incomplete fix for CVE-2026-35536: cookie attribute injection re-opened via the legacy case-insensitive `**kwargs` path in `set_cookie`

Summary The CVE-2026-35536 fix added a validation loop that rejects \x00-\x20\x3b\x7f, but only for the hardcoded lowercase keys name/domain/path/samesite. The still-live deprecated kwargs path writes attacker-supplied attribute values straight into the Morsel with no validation, and because...