Enable model selection in command page

[kivo360]

Problem

The command page (frontend/app/(app)/command/page.tsx ~line 359) has a commented-out model selector:

{/* TODO: Re-enable when model selection is ready */}
{/* <ModelSelector
  value={selectedModel}
  onValueChange={setSelectedModel}
/> */}

Users can't choose which LLM model to use for spec generation.

What to do

1. Review if the ModelSelector component is functional
2. Wire it to the backend's LLM service configuration
3. Enable the component in the command page
4. Ensure model selection persists across sessions

Difficulty: Easy-Medium | Skill: Frontend (React)