feat: Add Docker containerization with Gitea Actions

Dockerfile

@@ -0,0 +1,34 @@
+# Stage 1: Build nginx image with static content
+FROM nginx:alpine
+
+# Install dumb-init for proper signal handling
+RUN apk add --no-cache dumb-init
+
+# Copy custom nginx configuration
+COPY nginx.conf /etc/nginx/nginx.conf
+
+# Copy static site content to nginx html directory
+COPY karaoke.karaniwan.org/ /usr/share/nginx/html/
+
+# Create nginx user and set permissions
+RUN chown -R nginx:nginx /usr/share/nginx/html && \
+    chown -R nginx:nginx /var/cache/nginx && \
+    chown -R nginx:nginx /var/log/nginx && \
+    touch /var/run/nginx.pid && \
+    chown -R nginx:nginx /var/run/nginx.pid
+
+# Switch to non-root user
+USER nginx
+
+# Expose port 80
+EXPOSE 80
+
+# Add healthcheck
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+    CMD wget --no-verbose --tries=1 --spider http://localhost/ || exit 1
+
+# Use dumb-init to handle signals properly
+ENTRYPOINT ["/usr/bin/dumb-init", "--"]
+
+# Start nginx
+CMD ["nginx", "-g", "daemon off;"]