Update Dockerfile to copy built assets to nginx and use custom config

Dockerfile

@@ -3,13 +3,15 @@
 # ---------------------------------------------------------
 FROM node:18-alpine AS builder
 
-# Install git (needed by some npm postinstall scripts)
+# Install dependencies
 RUN apk add --no-cache git
 
 WORKDIR /app
 
-# Install dependencies (uses package-lock if present, otherwise npm install)
-COPY package.json package-lock.json* ./
+# Copy package files
+COPY package.json ./
+
+# Install dependencies
 RUN npm install
 
 # Copy source files
@@ -24,11 +26,8 @@ RUN npm run build
 # ---------------------------------------------------------
 FROM nginx:alpine
 
-# Remove default nginx config
-RUN rm /etc/nginx/conf.d/default.conf
-
-# Copy custom config
-COPY nginx.conf /etc/nginx/conf.d
+# Copy only our custom config
+COPY nginx.conf /etc/nginx/conf.d/default.conf
 
 # Copy built assets
 COPY --from=builder /app/dist /usr/share/nginx/html