Add HTTPS support with Caddy and clean up legacy files

- Add Caddy reverse proxy for automatic HTTPS with Let's Encrypt
- Update docker-compose.yml with Caddy service and internal networking
- Remove all Redis dependencies (not needed for this deployment)
- Fix Dockerfile permissions for instance and uploads directories
- Move legacy scripts to old_code_documentation folder
  - add_muted_column.py, check_fix_player.py, migrate_add_edit_enabled.py
  - docker-start.sh, run_dev.sh, start.sh, clean_for_deployment.sh
- Add HTTPS_SETUP.md documentation for Caddy configuration
- Update .env.example with DOMAIN and EMAIL variables
- Remove redis package from requirements.txt
- Remove rate limiting Redis storage from config.py

Caddyfile

@@ -0,0 +1,43 @@
+{
+    # Global options
+    email {$EMAIL}
+    # Uncomment for testing to avoid rate limits
+    # acme_ca https://acme-staging-v02.api.letsencrypt.org/directory
+}
+
+{$DOMAIN:localhost} {
+    # Automatic HTTPS (Caddy handles Let's Encrypt automatically)
+    
+    # Reverse proxy to Flask app
+    reverse_proxy digiserver:5000 {
+        # Headers
+        header_up Host {host}
+        header_up X-Real-IP {remote_host}
+        header_up X-Forwarded-For {remote_host}
+        header_up X-Forwarded-Proto {scheme}
+        
+        # Timeouts for large uploads
+        transport http {
+            read_timeout 300s
+            write_timeout 300s
+        }
+    }
+    
+    # File upload size limit (2GB)
+    request_body {
+        max_size 2GB
+    }
+    
+    # Security headers
+    header {
+        Strict-Transport-Security "max-age=31536000; includeSubDomains"
+        X-Frame-Options "SAMEORIGIN"
+        X-Content-Type-Options "nosniff"
+        X-XSS-Protection "1; mode=block"
+    }
+    
+    # Logging
+    log {
+        output file /var/log/caddy/access.log
+    }
+}