add-event-type

# Add Event Type

## Instructions
1. Read current event types in `frontend/src/App.tsx`:
   - Find the `EventType` union type definition
   - Review existing block components (UserMessageBlock, PlanBlock, TodoBlock, etc.)

2. Define the new event type interface:
   ```typescript
   type NewEventType = {
     type: 'new_type';
     // Add required fields
   };
   ```

3. Add to EventType union:
   ```typescript
   type EventType = UserMessage | Plan | Todo | ... | NewEventType;
   ```

4. Create a new block component following existing patterns:
   ```typescript
   function NewTypeBlock({ event }: { event: NewEventType }) {
     return (
       <div className="p-3 bg-zinc-800/50 rounded-lg border border-zinc-700/50">
         {/* Render event data */}
       </div>
     );
   }
   ```

5. Add case to the feed rendering switch/conditional in the main component

6. Update WebSocket message handler if backend sends this event type

## Examples
- "Add a new 'search_result' event type"
- "Create a block for displaying errors"
- "Add event type for progress updates"

## Guardrails
- Follow existing naming conventions (PascalCase components, snake_case event types)
- Use existing Tailwind classes for consistent styling
- Ensure TypeScript types are complete (no `any`)
- Test by sending mock event through WebSocket