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

tests/caddyfile.bats

@@ -158,7 +158,9 @@ CADDYFILE="$REPO_ROOT/dankclaw/Caddyfile"
     [ "$n" -ge 2 ] || { echo "expected >=2 busybox healthchecks, found $n"; return 1; }
 }
 
-@test "alloy config uses the ui component (the server component was renamed)" {
-    grep -qE '^ui \{' "$REPO_ROOT/shared/alloy/config.alloy"
-    ! grep -qE '^server \{' "$REPO_ROOT/shared/alloy/config.alloy"
+@test "alloy config declares no ui/server block (default UI listens on 127.0.0.1:12345)" {
+    # alloy 1.x refuses to configure the ui service from a config block
+    # ("service ui does not support being configured"). The default UI
+    # already listens where the in-container healthcheck probes.
+    ! grep -qE '^(ui|server) \{' "$REPO_ROOT/shared/alloy/config.alloy"
 }