Docker: add a step to reduce image size and use entrypoint

Dockerfile

@@ -3,9 +3,12 @@ FROM node:lts AS buildfront
 COPY front .
 RUN npm install && npm run build
 
-FROM golang:1.25
+FROM golang:1.25 AS build
 WORKDIR /src
 COPY . .
 COPY --from=buildfront ./dist front/dist
-RUN go build -tags=embed
-CMD ["./bibliomane", "-D", "-C", "-n"]
+RUN go build -tags=embed -o /bin/bibliomane
+
+FROM debian:bookworm
+COPY --from=build /bin/bibliomane /bin/bibliomane
+ENTRYPOINT ["/bin/bibliomane"]