refactor: backend port 8000 → 7000 pour eviter conflits applicatifs

- Dockerfile: EXPOSE + CMD uvicorn --port 7000
- app/config.py: PORT default 8000 → 7000
- nginx default.conf: 6x proxy_pass backend:8000 → backend:7000
- docker-compose.prod.yml: BACKEND_PORT default 8001 → 7000, internal 7000
- docker-compose.yml (dev): 8000:8000 → 7000:7000
- imago-admin/docker-compose.yml: VITE_API_BASE_URL + port mapping → 7000
- .env.example: BACKEND_PORT=8001 → 7000
- deploy.sh: defaults + invites port 8001 → 7000

app/config.py

@@ -18,7 +18,7 @@ class Settings(BaseSettings):
 
     # Serveur
     HOST: str = "0.0.0.0"
-    PORT: int = 8000
+    PORT: int = 7000
 
     # Base de données
     DATABASE_URL: str = "sqlite+aiosqlite:///./data/imago.db"