test: add session renewal and token recovery tests for WtSite

9 unit tests covering WtSite/WtPage try_and_renew_token decorators
(CSRF refresh, full relogin recovery, error propagation) and _relogin()
edge cases (legacy config, non-UserPwd credentials, correct login call).
3 live integration tests verifying recovery from invalid CSRF token,
expired session (cleared cookies), and cascading corruption.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: LukasGold