## Why
Standalone web search can return structured result DTOs separately from its
model-facing text output. App-server clients need access to that data without
coupling Codex to every result type or field.
## What changed
- Preserve the optional `results` array from `/v1/alpha/search` as opaque JSON
through web-search completion events, thread history, and app-server
`webSearch` items.
- Keep responses from older endpoints compatible when `results` is absent, and
allow clients to ignore result types and fields they do not understand.
- Regenerate the protocol schemas and TypeScript definitions for the optional
field.
## Testing
- Cover responses with missing, empty, and forward-compatible result payloads.
- Verify standalone web-search results round-trip through app-server item
notifications and thread-item conversion.
GitOrigin-RevId: 739ef5694ece5733f7b8749ec41d6bfa3f33c8c5