Update Dockerfile

Dockerfile

@@ -24,10 +24,11 @@ RUN npm run build
 # ── 3. Backend (Go) ───────────────────────────────────────
 FROM golang:1.22-alpine AS backend
 WORKDIR /app
+RUN apk add --no-cache gcc musl-dev
 COPY --from=unpacker /src/backend/go.mod /src/backend/go.sum ./
-RUN go mod download
+RUN go mod tidy && go mod download
 COPY --from=unpacker /src/backend/ .
-RUN CGO_ENABLED=0 GOOS=linux \
+RUN CGO_ENABLED=1 GOOS=linux \
     go build -ldflags="-s -w" -o server ./cmd/server
 
 # ── 4. Runtime ────────────────────────────────────────────
@@ -35,7 +36,7 @@ FROM python:3.11-slim
 WORKDIR /app
 
 RUN apt-get update && \
-    apt-get install -y --no-install-recommends ca-certificates && \
+    apt-get install -y --no-install-recommends ca-certificates libgcc-s1 && \
     rm -rf /var/lib/apt/lists/*
 
 # Go binary + frontend assets