feat: add Giphy API key as a build argument and environment variable.

Dockerfile

@@ -24,11 +24,13 @@ COPY . .
 
 # Accept build arguments
 ARG NEXT_PUBLIC_API_URL
+ARG NEXT_PUBLIC_GIPHY_API_KEY
 
 # Set environment variables for build (NEXT_PUBLIC_* must be set at build time)
 ENV NEXT_TELEMETRY_DISABLED=1
 ENV NODE_ENV=production
 ENV NEXT_PUBLIC_API_URL=${NEXT_PUBLIC_API_URL}
+ENV NEXT_PUBLIC_GIPHY_API_KEY=${NEXT_PUBLIC_GIPHY_API_KEY}
 
 # Build the application
 RUN npm run build