feat: health check for backend in docker-compose;

feat: go dockerfile preinstalls curl;
refactor: reduced go image size by using a 2 stage dockerfile;
refactor: switch frontend dockerfile

backend/Dockerfile

@@ -1,12 +1,30 @@
-FROM golang:1.24
+# Stage 1: Build the binary
+FROM golang:1.24 AS builder
 
-WORKDIR /usr/src/app
+WORKDIR /app
 
+# Copy dependencies and download
 COPY go.mod go.sum ./
 RUN go mod download
 
+# Copy source and build static binary
 COPY . .
-RUN go build -v -o /usr/local/bin/app ./...
+RUN CGO_ENABLED=0 go build -ldflags="-s -w" -o /main ./cmd/main.go
 
-CMD ["app"]
+# Stage 2: Lightweight runtime with tools
+FROM debian:bookworm-slim
 
+# Install curl, shell (sh), and SSL certificates
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends curl ca-certificates && \
+    rm -rf /var/lib/apt/lists/*
+
+# Create non-root user and set ownership
+RUN groupadd -r appuser && useradd -r -g appuser appuser
+USER appuser
+
+# Copy compiled binary
+COPY --from=builder /main /main
+
+# Execute the binary
+CMD ["/main"]