ci: build musl only for arm64 and reuse toolchain cache [CI]

packaging/container/Agent.Containerfile

@@ -1,4 +1,5 @@
-FROM mcr.microsoft.com/dotnet/runtime-deps:10.0-alpine
+ARG RUNTIME_BASE=mcr.microsoft.com/dotnet/runtime-deps:10.0
+FROM ${RUNTIME_BASE}
 
 ARG APP_VERSION=unknown
 LABEL org.opencontainers.image.title="MoShiro Agent" \
@@ -6,8 +7,7 @@ LABEL org.opencontainers.image.title="MoShiro Agent" \
       org.opencontainers.image.licenses="Apache-2.0" \
       org.opencontainers.image.version="$APP_VERSION"
 
-COPY --chown=1654:1654 app/moshiro-agent /usr/local/bin/moshiro-agent
-COPY --chown=1654:1654 app/fleet-enroll /usr/local/bin/fleet-enroll
+COPY --chown=1654:1654 app/ /usr/local/bin/
 COPY --chown=1654:1654 config/ /etc/moshiro/
 COPY --chown=1654:1654 --chmod=0755 entrypoint.sh /usr/local/bin/moshiro-entrypoint