2d90ed62f3
- Added RedactedThinkingContent type to support secure encrypted reasoning blocks in Anthropic messages. - Updated message transformation logic to preserve signed thinking blocks and redacted thinking for latest assistant messages in Anthropic conversations. - Added handling for redacted_thinking events in Anthropic stream processing with type, data, and index fields. - Added comprehensive tests validating redacted thinking block preservation and Anthropic thinking immutability during message transformation.