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

app/config.py

@@ -29,6 +29,11 @@ class Config:
     SESSION_COOKIE_HTTPONLY = True
     SESSION_COOKIE_SAMESITE = 'Lax'
     
+    # Reverse proxy trust (for Nginx/Caddy with ProxyFix middleware)
+    # These are set by werkzeug.middleware.proxy_fix
+    TRUSTED_PROXIES = os.getenv('TRUSTED_PROXIES', '127.0.0.1,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16')
+    PREFERRED_URL_SCHEME = os.getenv('PREFERRED_URL_SCHEME', 'https')
+    
     # Cache
     SEND_FILE_MAX_AGE_DEFAULT = 300  # 5 minutes for static files