Redmine/requests exceptions may embed the request URL containing the
API key (?key=SECRET) or the X-Redmine-API-Key header value. The CLI
printed the raw exception text to stderr, leaking the key into
terminals and logs.
Add _sanitize_error_text() which masks 'key=<value>' query params and
the X-Redmine-API-Key header as 'key=***' / 'X-Redmine-API-Key: ***',
and apply it to every exception-derived message printed to stderr
(fetch errors in main() and SMTP errors in _save_and_maybe_send()).
Full traceback with original exception details is now available under
both --verbose and --debug (previously only --debug, only for
RedmineAPIError). Exit codes and error-handling structure unchanged.
Closes#55
fb1ca1d9b8