observability: fix alloy ui component, busybox healthchecks for loki/alloy

- alloy 1.x renamed the server component to ui; the old block failed the
  initial load and the container crash-looped
- grafana/loki is distroless and grafana/alloy lacks wget, so their
  healthchecks could never run; local images add a static busybox from
  alpine for that one command
- deploy.sh builds all three local images if missing
- tests: 3 new seams

dankclaw/loki/Containerfile

@@ -0,0 +1,15 @@
+# Loki + a static busybox.
+#
+# grafana/loki is distroless: no shell, no wget, so the compose healthcheck
+# cannot run anything inside the container. This image drops a static
+# busybox into it for the healthcheck command only. All Loki behavior is
+# unchanged.
+#
+# Build on dankclaw:
+#   podman build -t franksdank/loki:latest -f dankclaw/loki/Containerfile .
+
+FROM docker.io/library/alpine:latest AS tools
+# busybox provides wget for the healthcheck.
+
+FROM docker.io/grafana/loki:latest
+COPY --from=tools /bin/busybox /usr/local/bin/busybox