Fix HF Docker build by replacing npm ci with npm install

Dockerfile

@@ -9,7 +9,7 @@ FROM node:20-slim AS frontend-builder
 WORKDIR /build
 
 COPY codesentry-frontend/package.json codesentry-frontend/package-lock.json ./
-RUN npm ci
+RUN npm install
 
 COPY codesentry-frontend/ ./
 # In HF Spaces the frontend talks to the same origin (backend serves static)