Add self-hosting capabilities and deployment guide for the application

Implement self-hosting for RockyLinux by adding systemd and Nginx configurations, updating API models to support standard OpenAI keys, and providing a comprehensive deployment guide.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 923ae0e3-a363-4db8-b04a-e8baca2a1330
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: f8aa455f-f180-4964-94dd-11cfb1a42383
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/8af7d2ec-2cc3-4ece-8af3-9f071488d072/923ae0e3-a363-4db8-b04a-e8baca2a1330/VnHW0bR
Replit-Helium-Checkpoint-Created: true

deploy/voix-du-peuple-api.service

@@ -0,0 +1,29 @@
+[Unit]
+Description=La Voix du Peuple — API Flask
+After=network.target postgresql.service
+Requires=postgresql.service
+
+[Service]
+Type=exec
+User=voixdupeuple
+Group=voixdupeuple
+WorkingDirectory=/opt/voix-du-peuple/artifacts/flask-api
+EnvironmentFile=/opt/voix-du-peuple/.env
+ExecStart=/opt/voix-du-peuple/.venv/bin/gunicorn \
+    --workers 4 \
+    --bind 127.0.0.1:8000 \
+    --access-logfile /var/log/voix-du-peuple/api-access.log \
+    --error-logfile /var/log/voix-du-peuple/api-error.log \
+    --timeout 60 \
+    app:app
+Restart=always
+RestartSec=5
+
+# Sécurité
+NoNewPrivileges=true
+PrivateTmp=true
+ProtectSystem=strict
+ReadWritePaths=/var/log/voix-du-peuple
+
+[Install]
+WantedBy=multi-user.target