feat(desktop): add reviewer/model selection UI for local review

[justn-hyeok]

Problem

Desktop can run reviews, but users cannot choose reviewers/models from the UI before launching.

Source

docs/DESKTOP_APP_CONSOLIDATION.md lists reviewer/model selection as a TUI capability to absorb.

Acceptance Criteria

• Run Review view shows current reviewer/model config.
• User can choose or edit reviewer/model selection without inventing desktop-only config semantics.
• Changes round-trip through canonical config/CLI contracts.
• Typecheck and smoke pass.