Docker: enable BuildKit cache for npm ci

Dockerfile

@@ -7,16 +7,18 @@ WORKDIR /app
 ENV npm_config_update_notifier=false \
     npm_config_audit=false \
     npm_config_fund=false \
-    npm_config_progress=false
+    npm_config_progress=false \
+    ASTRO_TELEMETRY_DISABLED=1
 
 # (Optionnel mais propre) git + certificats
 RUN apt-get -o Acquire::Retries=5 -o Acquire::ForceIPv4=true update \
  && apt-get install -y --no-install-recommends ca-certificates git \
- && rm -rf /var/lib/apt/lists/*	
+ && rm -rf /var/lib/apt/lists/*
 
 # Déps d’abord (cache Docker)
 COPY package.json package-lock.json ./
-RUN npm ci --no-audit --no-fund
+RUN --mount=type=cache,target=/root/.npm \
+    npm ci --no-audit --no-fund
 
 # Sources
 COPY . .