## Why
Clients need to know whether a `request_user_input` request must wait for an
explicit response or may auto-resolve. Using `autoResolutionMs` as that signal
conflated the blocking decision with timeout policy.
## What changed
- Add required `isBlocking` fields to user input protocol and app-server
request payloads. Plan-mode requests are blocking, while requests from other
enabled modes are non-blocking.
- Drive the TUI's auto-resolution behavior from `isBlocking` and remove
`autoResolutionMs` from the model-facing tool schema.
- Deprecate `autoResolutionMs` while retaining it for compatibility, and treat
legacy payloads without `isBlocking` as blocking.
## Testing
- Cover mode-derived blocking behavior, legacy deserialization, app-server
forwarding, delegated requests, and TUI auto-resolution.
GitOrigin-RevId: 29aade657ef743065ec264376ba567a9b353d7d7
