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/compose.yaml

@@ -149,7 +149,8 @@ services:
       retries: 3
 
   loki:
-    image: docker.io/grafana/loki:latest
+    # Local build: grafana/loki + static busybox (healthcheck).
+    image: franksdank/loki:latest
     container_name: loki
     restart: unless-stopped
     # Rootless: container root maps to the invoking user (dank), which
@@ -163,13 +164,14 @@ services:
       - /opt/loki/config:/etc/loki
       - /opt/loki/data:/loki
     healthcheck:
-      test: ["CMD", "wget", "--spider", "-q", "http://localhost:3100/ready"]
+      test: ["CMD", "/usr/local/bin/busybox", "wget", "--spider", "-q", "http://localhost:3100/ready"]
       interval: 30s
       timeout: 10s
       retries: 3
 
   alloy:
-    image: docker.io/grafana/alloy:latest
+    # Local build: grafana/alloy + static busybox (healthcheck).
+    image: franksdank/alloy:latest
     container_name: alloy
     restart: unless-stopped
     volumes:
@@ -180,7 +182,7 @@ services:
     depends_on:
       - loki
     healthcheck:
-      test: ["CMD", "wget", "--spider", "-q", "http://localhost:12345/-/healthy"]
+      test: ["CMD", "/usr/local/bin/busybox", "wget", "--spider", "-q", "http://localhost:12345/-/healthy"]
       interval: 30s
       timeout: 10s
       retries: 3