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

imago-admin/nginx/default.conf

@@ -11,7 +11,7 @@ server {
 
     # Proxy vers le backend pour les routes API (v1 et Admin)
     location /api/ {
-        proxy_pass http://backend:8000;
+        proxy_pass http://backend:7000;
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
@@ -20,7 +20,7 @@ server {
 
     # Proxy pour les fichiers signés (thumbnails, downloads)
     location /files/ {
-        proxy_pass http://backend:8000;
+        proxy_pass http://backend:7000;
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
@@ -28,7 +28,7 @@ server {
     }
 
     location /admin/api/ {
-        proxy_pass http://backend:8000;
+        proxy_pass http://backend:7000;
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
@@ -36,18 +36,18 @@ server {
     }
 
     location /ws/ {
-        proxy_pass http://backend:8000;
+        proxy_pass http://backend:7000;
         proxy_http_version 1.1;
         proxy_set_header Upgrade $http_upgrade;
         proxy_set_header Connection "upgrade";
     }
 
     location /health {
-        proxy_pass http://backend:8000;
+        proxy_pass http://backend:7000;
     }
 
     location /metrics {
-        proxy_pass http://backend:8000;
+        proxy_pass http://backend:7000;
     }
 
     # Cache agressif pour les assets buildés (hash dans le nom)