Wire all 25 services into --randomize-services and add heterogeneous OS fingerprints

- Replace hardcoded ALL_SERVICE_NAMES=[5 services] in cli.py with
  _all_service_names() pulling dynamically from the plugin registry;
  randomize-services now draws from all 25 registered honeypots
- Add build_base field to DistroProfile: apt-compatible image for service
  Dockerfiles (ubuntu22/ubuntu20/kali get their own; others fall back to
  debian:bookworm-slim since Dockerfiles use apt-get)
- Add build_base to DeckyConfig; propagate from distro in _build_deckies
  and _build_deckies_from_ini
- Inject BASE_IMAGE build arg in composer.py for every build-based service
  so each decky's containers reflect its assigned distro
- Update all 21 service Dockerfiles: FROM debian:bookworm-slim →
  ARG BASE_IMAGE=debian:bookworm-slim / FROM ${BASE_IMAGE}
- Add tests/test_cli_service_pool.py and tests/test_composer.py (306 total)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

decnet/composer.py

@@ -48,6 +48,11 @@ def generate_compose(config: DecnetConfig) -> dict:
             svc = get_service(svc_name)
             fragment = svc.compose_fragment(decky.name, log_target=config.log_target)
 
+            # Inject the per-decky base image into build services so containers
+            # vary by distro and don't all fingerprint as debian:bookworm-slim.
+            if "build" in fragment:
+                fragment["build"].setdefault("args", {})["BASE_IMAGE"] = decky.build_base
+
             fragment.setdefault("environment", {})
             fragment["environment"]["HOSTNAME"] = decky.hostname