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

Dockerfile

@@ -22,6 +22,6 @@ COPY . .
 # Répertoires de données
 RUN mkdir -p data/uploads data/thumbnails
 
-EXPOSE 8000
+EXPOSE 7000
 
-CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]
+CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "7000"]