calibre-web-automated: fix healthcheck (curl, not wget)

CWA image ships curl and busybox nc but no wget, so the initial
healthcheck wedged the container in unhealthy state. Swap to curl -fsS
hitting the login page; compose-time substitution of CWA_PORT keeps
custom port overrides working.

stacks/calibre-web-automated/compose.yaml

@@ -25,7 +25,11 @@ services:
       - ${CWA_INGEST_DIR}:/cwa-book-ingest
       - ${CWA_LIBRARY_DIR}:/calibre-library
     healthcheck:
-      test: ["CMD-SHELL", "wget -q --spider http://localhost:${CWA_PORT:-8083} || exit 1"]
+      # CWA image ships curl (not wget). `-fsS` makes curl exit non-zero on
+      # 4xx/5xx or connection failure while staying quiet on success. The
+      # port substitution happens at compose-render time so custom CWA_PORT
+      # values still work.
+      test: ["CMD", "curl", "-fsS", "-o", "/dev/null", "http://localhost:${CWA_PORT:-8083}/"]
       interval: 30s
       timeout: 10s
       retries: 3