feat: add Docker build

Dockerfile

@@ -0,0 +1,31 @@
+# Build stage
+FROM golang:1.24-alpine AS builder
+
+WORKDIR /app
+
+# Copy go mod files
+COPY go.mod go.sum ./
+RUN go mod download
+
+# Copy source code
+COPY . .
+
+# Build the application
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o spore-gateway ./main.go
+
+# Runtime stage
+FROM alpine:latest
+
+RUN apk --no-cache add ca-certificates
+
+WORKDIR /root/
+
+# Copy the binary from builder
+COPY --from=builder /app/spore-gateway .
+
+# Expose ports
+EXPOSE 3001 4210
+
+# Run the application
+CMD ["./spore-gateway"]
+