Fix Docker Go build stage

Dockerfile

@@ -1,9 +1,9 @@
 FROM golang:1.24-bookworm AS go-builder
 WORKDIR /src
-COPY go.mod ./
+COPY go.mod go.sum ./
 RUN go mod download
 COPY backend ./backend
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o /out/ai-media-hub ./backend
+RUN go build -o /out/ai-media-hub ./backend
 
 FROM python:3.12-slim-bookworm
 ENV APP_ROOT=/app