Add Docker setup for Alma-vid React app

Introduces Dockerfile, docker-compose.yml, .dockerignore, nginx.conf, and a Docker-specific README to enable containerized builds and deployment for the React application using Node.js and nginx. Includes optimized nginx configuration for static assets, security headers, gzip compression, and React Router support.

nginx.conf

@@ -0,0 +1,70 @@
+user nginx;
+worker_processes auto;
+error_log /var/log/nginx/error.log warn;
+pid /var/run/nginx.pid;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+    include /etc/nginx/mime.types;
+    default_type application/octet-stream;
+
+    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
+                    '$status $body_bytes_sent "$http_referer" '
+                    '"$http_user_agent" "$http_x_forwarded_for"';
+
+    access_log /var/log/nginx/access.log main;
+
+    sendfile on;
+    tcp_nopush on;
+    tcp_nodelay on;
+    keepalive_timeout 65;
+    types_hash_max_size 2048;
+
+    # Gzip compression
+    gzip on;
+    gzip_vary on;
+    gzip_min_length 1024;
+    gzip_proxied any;
+    gzip_comp_level 6;
+    gzip_types
+        text/plain
+        text/css
+        text/xml
+        text/javascript
+        application/json
+        application/javascript
+        application/xml+rss
+        application/atom+xml
+        image/svg+xml;
+
+    server {
+        listen 80;
+        server_name localhost;
+        root /usr/share/nginx/html;
+        index index.html;
+
+        # Security headers
+        add_header X-Frame-Options "SAMEORIGIN" always;
+        add_header X-XSS-Protection "1; mode=block" always;
+        add_header X-Content-Type-Options "nosniff" always;
+        add_header Referrer-Policy "no-referrer-when-downgrade" always;
+        add_header Content-Security-Policy "default-src 'self' http: https: data: blob: 'unsafe-inline'" always;
+
+        # Static files cache
+        location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg)$ {
+            expires 1y;
+            add_header Cache-Control "public, immutable";
+        }
+
+        # Handle React Router
+        location / {
+            try_files $uri $uri/ /index.html;
+        }
+
+        # Error pages
+        error_page 404 /index.html;
+    }
+}