build: change Dockerfile base to Debian

Dockerfile

@@ -1,5 +1,5 @@
 # Build-Phase
-FROM node:20-alpine AS builder
+FROM node:20-slim AS builder
 WORKDIR /app
 COPY package*.json ./
 RUN npm install --legacy-peer-deps
@@ -7,7 +7,7 @@ COPY . .
 RUN npm run build
 
 # Production-Phase
-FROM nginx:alpine
+FROM nginx:1.25
 
 # Nginx konfigurieren für non-root Port 8080
 RUN sed -i 's/listen\( \)*80;/listen 8080;/g' /etc/nginx/conf.d/default.conf && \