Fix code review issues: update datetime.utcnow() to datetime.now(timezone.utc) and fix Docker configs

Co-authored-by: mblanke <9078342+mblanke@users.noreply.github.com>

frontend/.dockerignore

@@ -0,0 +1,8 @@
+node_modules
+npm-debug.log
+build
+.git
+.gitignore
+README.md
+.env
+.env.local

frontend/Dockerfile

@@ -3,7 +3,8 @@ FROM node:18-alpine
 WORKDIR /app
 
 # Copy package files
-COPY package*.json ./
+COPY package.json ./
+COPY package-lock.json* ./
 
 # Install dependencies
 RUN npm install