SACRAMENTO — Agents who investigate wrongdoing in state prisons have been ordered not to disclose information about any aspect of their work to legislators, the media or the governor's office — and told to sign a pledge committing to follow the confidentiality rules or face possible sanctions. The directive, contained in a memo obtained by The Times, was issued as two state senators prepare to hold hearings on misconduct and coverups within the Department of Corrections, including a "code of silence" that often protects rogue guards. On Thursday, both senators expressed concern that the memo might discourage whistle-blowers from reporting...