fix(infra) : add deploy.sh with maintenance mode like Inventory

Maintenance is handled by nginx-proxy on the host, not inside the
container. deploy.sh extracts maintenance.html from the container.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

infra/prod/nginx.conf

@@ -10,16 +10,6 @@ server {
     access_log /dev/stdout;
     error_log /dev/stderr;
 
-    # Mode maintenance : créer /var/www/html/maintenance.on pour activer
-    if (-f /var/www/html/maintenance.on) {
-        return 503;
-    }
-    error_page 503 @maintenance;
-    location @maintenance {
-        root /var/www/html/public;
-        rewrite ^(.*)$ /maintenance.html break;
-    }
-
     location ^~ /api/ {
         root /var/www/html/public;
         try_files $uri /index.php?$query_string;