Add Brave Search as primary web search with NanoGPT fallback

- Brave Search API is now primary (if BRAVE_API_KEY set)
- NanoGPT web search is fallback if Brave fails
- Add BRAVE_API_KEY to .env, docker-compose, and deploy workflow
- Tool calling still works for AI to request searches

docker-compose.yml

@@ -10,6 +10,7 @@ services:
     environment:
       - NANO_MODEL=${NANO_MODEL}
       - ZAI_API_KEY=${ZAI_API_KEY}
+      - BRAVE_API_KEY=${BRAVE_API_KEY}
     volumes:
       # Mount logs directory if you want to persist logs
       - ./logs:/app/logs