Remove portfolio network for Coolify compatibility

- Remove custom 'portfolio' network definition
- Coolify creates its own network per deployment
- Having both networks causes Traefik routing conflicts
- Containers were connecting to wrong network IP

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

docker-compose.yml

@@ -24,9 +24,6 @@ services:
       retries: 3
       start_period: 40s
 
-    networks:
-      - portfolio
-
   # Astro Frontend
   frontend:
     build:
@@ -53,11 +50,3 @@ services:
       timeout: 10s
       retries: 3
       start_period: 40s
-
-    networks:
-      - portfolio
-
-networks:
-  portfolio:
-    name: portfolio
-    external: false