- Extend CompanionDefinition with avatarUrl field using Vite static imports
- Replace emoji-only companion cards with avatar img + onerror emoji fallback
- Add companion-card__avatar CSS (80px round) and companion-area styles (48px)
- Add vite-env.d.ts for PNG import type declarations
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>