## What changed
- Add a `ResponseItemId` type that generates item-specific prefixes with UUIDv7 suffixes and use it across response items.
- Keep deserialization permissive for legacy histories, but omit empty or unprefixed item IDs from HTTP and WebSocket requests.
- Export the new type in the generated TypeScript protocol schema.
## Testing
- Cover prefixed ID generation, legacy deserialization, prefix recognition, and outbound request filtering.
GitOrigin-RevId: 0209fe430c826d0ae88bc4648652c4ebf390c4a4