Update README.md with Docker build and Kubernetes debug instructions

- Added instructions for building and pushing Docker images with specific tags.
- Included steps for creating Kubernetes secrets from local .env files.
- Provided guidance on manually creating and removing a debug pod in Kubernetes.

Dockerfile.debug

@@ -0,0 +1,19 @@
+FROM golang:1.25-bookworm AS build
+
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY cmd/ ./cmd/
+COPY internal/ ./internal/
+RUN CGO_ENABLED=0 GOOS=linux go build -trimpath -ldflags="-s -w" -o /out/ncore-hnr ./cmd/ncore-hnr
+
+FROM alpine:3.20
+
+RUN apk add --no-cache bash ca-certificates curl bind-tools sqlite
+
+WORKDIR /app
+COPY --from=build /out/ncore-hnr /usr/local/bin/ncore-hnr
+
+VOLUME ["/data"]
+CMD ["/bin/sh"]