## What changed
- Convert MCP text content marked with `_meta["codex/encryptedContent"] = true`
into `encrypted_content` function call output items.
- Prefer the content-item payload whenever encrypted content is present so that
`structured_content` does not replace the encrypted output.
## Testing
- Add a stdio MCP integration test that round-trips mixed plaintext and
encrypted tool output.
GitOrigin-RevId: c3997a16b06ad38ff22b21016ede35b97974d9ec