add a docker file and generate certs and more makefile notes

Dockerfile

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+FROM golang:1.24-alpine AS builder
+
+WORKDIR /workspace
+
+# Copy go mod files
+COPY go.mod go.mod
+COPY go.sum go.sum
+
+# Cache dependencies
+RUN go mod download
+
+# Copy source code
+COPY main.go main.go
+
+# Build
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -a -o webhook main.go
+
+# Use distroless as minimal runtime image
+FROM gcr.io/distroless/static:nonroot
+
+WORKDIR /
+COPY --from=builder /workspace/webhook .
+
+USER 65532:65532
+
+ENTRYPOINT ["/webhook"]