Add Dockerfile, docker-compose.yml and Gitea Actions workflow for CI/CD

Dockerfile

@@ -0,0 +1,19 @@
+# Build-Phase
+FROM node:20-alpine AS builder
+WORKDIR /app
+COPY package*.json ./
+RUN npm install --legacy-peer-deps
+COPY . .
+RUN npm run build
+
+# Production-Phase
+FROM nginx:alpine
+
+# Nginx konfigurieren für non-root Port 8080
+RUN sed -i 's/listen\( \)*80;/listen 8080;/g' /etc/nginx/conf.d/default.conf && \
+    touch /var/run/nginx.pid && \
+    chown -R nginx:nginx /var/run/nginx.pid /var/cache/nginx /var/log/nginx /etc/nginx/conf.d
+
+USER nginx
+COPY --from=builder /app/dist /usr/share/nginx/html
+EXPOSE 8080