feat: complete nginx migration from caddy

- Replace Caddy reverse proxy with Nginx (nginx:alpine)
- Add nginx.conf with HTTP/HTTPS, gzip, and proxy settings
- Add nginx-custom-domains.conf template for custom domains
- Update docker-compose.yml to use Nginx service
- Add ProxyFix middleware to Flask app for proper header handling
- Create nginx_config_reader.py utility to read Nginx configuration
- Update admin blueprint to display Nginx status in https_config page
- Add Nginx configuration display to https_config.html template
- Generate self-signed SSL certificates for localhost
- Add utility scripts: generate_nginx_certs.sh
- Add documentation: NGINX_SETUP_QUICK.md, PROXY_FIX_SETUP.md
- All containers now running, HTTPS working, HTTP redirects to HTTPS
- Session cookies marked as Secure
- Security headers properly configured

docker-compose.yml

@@ -26,19 +26,19 @@ services:
     networks:
       - digiserver-network
 
-  # Caddy reverse proxy with automatic HTTPS
-  caddy:
-    image: caddy:2-alpine
-    container_name: digiserver-caddy
+  # Nginx reverse proxy with HTTPS support
+  nginx:
+    image: nginx:alpine
+    container_name: digiserver-nginx
     ports:
       - "80:80"
       - "443:443"
-      - "443:443/udp"  # HTTP/3 support
-      - "2019:2019"     # Caddy admin API
     volumes:
-      - ./data/Caddyfile:/etc/caddy/Caddyfile:ro
-      - ./data/caddy-data:/data
-      - ./data/caddy-config:/config
+      - ./nginx.conf:/etc/nginx/nginx.conf:ro
+      - ./nginx-custom-domains.conf:/etc/nginx/conf.d/custom-domains.conf:rw
+      - ./data/nginx-ssl:/etc/nginx/ssl:ro
+      - ./data/nginx-logs:/var/log/nginx
+      - ./data/certbot:/var/www/certbot:ro  # For Let's Encrypt ACME challenges
     environment:
       - DOMAIN=${DOMAIN:-localhost}
       - EMAIL=${EMAIL:-admin@localhost}
@@ -46,6 +46,12 @@ services:
       digiserver-app:
         condition: service_started
     restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "wget", "--quiet", "--tries=1", "--spider", "http://localhost:80/"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+      start_period: 10s
     networks:
       - digiserver-network