add: app_key dockerfile

Dockerfile

@@ -60,8 +60,10 @@ RUN npm ci
 # Build-time variables (set as HuggingFace Space Variables, not Secrets)
 ARG RAG_API_BASE_URL
 ARG VITE_APP_NAME="RAG Hub"
+ARG APP_KEY=base64:AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 ENV RAG_API_BASE_URL=$RAG_API_BASE_URL \
-    VITE_APP_NAME=$VITE_APP_NAME
+    VITE_APP_NAME=$VITE_APP_NAME \
+    APP_KEY=$APP_KEY
 
 # Source code
 COPY --chown=user:user . .