feat: Control features with build arg

Dockerfile

@@ -6,6 +6,10 @@ RUN rm -rf node_modules
 RUN rm -rf build
 RUN npm install
 COPY src/frontend/. .
+
+ARG feature_flag=false
+ENV VITE_FEATURE_FLAG=$feature_flag
+
 RUN npm run build
 # Thanks https://stackoverflow.com/q/76988450
 
@@ -40,6 +44,9 @@ RUN ln -s /app/src/pdf/fonts /tmp/fonts
 
 WORKDIR /app/src
 
+ARG feature_flag=false
+ENV VITE_FEATURE_FLAG=$feature_flag
+
 EXPOSE 80
 
 CMD [ "uv", "run", "main.py"]