busybox-static for healthchecks; alloy: rely on the default UI listener

- alpine's /bin/busybox is musl-dynamic and cannot execute in the
  distroless loki image (missing loader); busybox-static links in
- alloy 1.x refuses to configure the ui service from a config block;
  the default UI already listens on 127.0.0.1:12345 where the
  healthcheck probes

dankclaw/loki/Containerfile

@@ -9,7 +9,10 @@
 #   podman build -t franksdank/loki:latest -f dankclaw/loki/Containerfile .
 
 FROM docker.io/library/alpine:latest AS tools
-# busybox provides wget for the healthcheck.
+# busybox-static is statically linked: the target images have no dynamic
+# loader (loki is distroless), so the alpine default /bin/busybox (musl
+# dynamic) would fail with "no such file or directory".
+RUN apk add --no-cache busybox-static
 
 FROM docker.io/grafana/loki:latest
 COPY --from=tools /bin/busybox /usr/local/bin/busybox