Build from local KamadoPool checkout via buildx build-context

Replaces the git-clone-at-SHA source stage with a 'FROM scratch
AS source' stage that COPYs from a named build context. The
Makefile passes '--build-context kamado=../KamadoPool' by
default; override with 'make KAMADO_SRC=/elsewhere'. No more
SHA placeholder, no GitHub dependency, no re-clone on every
build — and the image always reflects the working tree.

Dockerfile

@@ -2,31 +2,24 @@
 #
 # Kamado Pool StartOS package image.
 #
-# Clones the KamadoPool repo at a pinned SHA, then inlines the ckpool,
-# ui, and api build stages (mirroring ckpool/Dockerfile and api/Dockerfile
-# in the upstream repo). Final runtime image has both binaries plus the
-# StartOS entrypoint that supervises them.
+# KamadoPool source is supplied via a named build context so the image
+# is built from the local checkout (no GitHub, no pinned SHA). The
+# Makefile passes `--build-context kamado=../KamadoPool` — adjust if
+# your checkout lives elsewhere.
 #
-# TODO: set KAMADO_SHA to a real pushed commit before running `make`.
-# The placeholder below is a valid 40-char hex string to keep tooling
-# happy but the clone checkout will fail until this is updated.
+# After the source stage, the ckpool/ui/api build steps mirror the
+# stages in KamadoPool's own ckpool/Dockerfile and api/Dockerfile.
 
-ARG KAMADO_REPO=https://github.com/Relaxo143/KamadoPool.git
-ARG KAMADO_SHA=0000000000000000000000000000000000000000
 ARG CKPOOL_REPO=https://bitbucket.org/ckolivas/ckpool.git
 ARG CKPOOL_COMMIT=cfb0f83b70d7b382b85d2bd0710cf4cb2dda4007
 ARG ARCH
 
-# ---------- stage 1: fetch Kamado 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 1: materialize Kamado source ----------
+# `kamado` is a named build context — the Makefile passes
+# --build-context kamado=../KamadoPool so this COPY pulls directly
+# from the local checkout.
+FROM scratch AS source
+COPY --from=kamado . /src/kamado/
 
 # ---------- stage 2: build patched ckpool ----------
 # Mirrors KamadoPool/ckpool/Dockerfile: clones upstream ckpool at the