Initial StartOS 0.3.5.1 packaging scaffold for Kamado Pool

Multi-stage Dockerfile clones KamadoPool at a pinned SHA, builds
ckpool and kamado-api (with embedded Svelte UI), runtime image
supervises both processes via tini + wait -n. Config covers
bitcoind mainnet/testnet4 variant, payout address, coinbase tag,
vardiff knobs, and log level. Web UI interface only — stratum
:3333 requires a router port-forward or simpleproxy workaround
because StartOS 0.3.x does not forward raw TCP on LAN.

TODO before first build: pin KAMADO_REPO + KAMADO_SHA in the
Dockerfile to a pushed commit.

Dockerfile

@@ -0,0 +1,87 @@
+# syntax=docker/dockerfile:1.6
+#
+# Kamado Pool StartOS package image.
+#
+# Clones KamadoPool at a pinned SHA, builds the patched ckpool-solo
+# binary, builds the Go api binary with embedded Svelte UI, then
+# assembles a small runtime image that supervises both processes.
+#
+# TODO: set KAMADO_REPO + KAMADO_SHA to a pushed commit before
+# running `make` — the defaults below are placeholders and the build
+# WILL fail until the KamadoPool source repo is pushed to GitHub.
+
+ARG KAMADO_REPO=https://github.com/Relaxo143/KamadoPool.git
+ARG KAMADO_SHA=REPLACE_ME_WITH_PUSHED_COMMIT_SHA
+ARG ARCH
+
+# ---------- stage 1: fetch source ----------
+FROM debian:bookworm-slim AS source
+ARG KAMADO_REPO
+ARG KAMADO_SHA
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        git ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+WORKDIR /src
+RUN git clone "${KAMADO_REPO}" kamado \
+    && cd kamado && git checkout "${KAMADO_SHA}"
+
+# ---------- stage 2: build ckpool ----------
+FROM debian:bookworm-slim AS ckpool-build
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        build-essential autoconf automake libtool pkg-config \
+        yasm libzmq3-dev git ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+COPY --from=source /src/kamado /src/kamado
+WORKDIR /src/kamado
+RUN make ckpool-src \
+    && cd ckpool/src \
+    && ./autogen.sh \
+    && ./configure --without-ckdb --prefix=/usr/local \
+    && make -j"$(nproc)" \
+    && install -Dm755 src/ckpool /out/usr/local/bin/ckpool
+
+# ---------- stage 3: build UI ----------
+FROM node:22-bookworm-slim AS ui-build
+WORKDIR /ui
+COPY --from=source /src/kamado/ui/package.json ./
+RUN npm install --no-audit --no-fund
+COPY --from=source /src/kamado/ui/ ./
+RUN npm run build
+
+# ---------- stage 4: build Go api with embedded UI ----------
+FROM golang:1.22-bookworm AS api-build
+WORKDIR /src
+COPY --from=source /src/kamado/api/ ./
+RUN rm -rf internal/webui/dist && mkdir -p internal/webui/dist
+COPY --from=ui-build /ui/dist/ internal/webui/dist/
+RUN CGO_ENABLED=0 GOOS=linux go build \
+        -trimpath -ldflags="-s -w" \
+        -o /out/kamado-api ./cmd/kamado-api
+
+# ---------- stage 5: runtime ----------
+FROM debian:bookworm-slim AS runtime
+ARG ARCH
+ARG YQ_VERSION=v4.44.3
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        tini ca-certificates curl libzmq5 \
+    && rm -rf /var/lib/apt/lists/*
+
+# yq for parsing StartOS config.yaml inside the entrypoint
+RUN set -eu; \
+    case "${ARCH}" in \
+      x86_64|amd64) YQ_ARCH=amd64 ;; \
+      aarch64|arm64) YQ_ARCH=arm64 ;; \
+      *) echo "unsupported arch: ${ARCH}" >&2; exit 1 ;; \
+    esac; \
+    curl -fsSL -o /usr/local/bin/yq \
+        "https://github.com/mikefarah/yq/releases/download/${YQ_VERSION}/yq_linux_${YQ_ARCH}"; \
+    chmod +x /usr/local/bin/yq
+
+COPY --from=ckpool-build /out/usr/local/bin/ckpool /usr/local/bin/ckpool
+COPY --from=api-build /out/kamado-api /usr/local/bin/kamado-api
+COPY docker_entrypoint.sh /usr/local/bin/docker_entrypoint.sh
+RUN chmod +x /usr/local/bin/docker_entrypoint.sh
+
+EXPOSE 3333 8080
+WORKDIR /root
+ENTRYPOINT ["/usr/bin/tini", "--", "/usr/local/bin/docker_entrypoint.sh"]