- Add model selector chip/dropdown in ChatInput with 4 models (llama3.2, claude-3.5-sonnet, gpt-4o, deepseek-r1)
- Add temperature slider (0.0–2.0) and max tokens input (100–32000) via settings popover
- Persist model, temperature, and max tokens in localStorage across sessions
- Wire model/temperature/maxTokens state up through Chat.tsx to useChat hook
- Add ChatEmptyState component with greeting and 4 clickable suggested prompts
- Clicking a suggestion pre-fills the ChatInput textarea via externalValue prop
- Add Cmd/Ctrl+N and Cmd/Ctrl+L keyboard shortcuts to start new conversation
- Add "New conversation" button in ChatOverlay header with Cmd+N tooltip
- Show ChatEmptyState when conversation has only the welcome message
- Write 63 tests covering model selector, params config, empty state, and keyboard shortcuts
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
