fix: update npm ci flag from --only=production to --omit=dev and remove nginx build job

Dockerfile

@@ -24,7 +24,7 @@ RUN apk add --no-cache curl su-exec util-linux && \
 
 # Install production dependencies only
 COPY package*.json ./
-RUN npm ci --only=production && \
+RUN npm ci --omit=dev && \
     npm cache clean --force
 
 # Copy built application