Phase 1: Cluster-Fundament – Nachrichten, Registry, Paarung, Discovery

- hms_cluster: ClusterMessage (§6.5: Pflichtfelder, Sequenzen, Revisionen,
  execute_at, Trace-ID), CommandTracker (idempotent, vorwärts-only:
  accepted->armed->executed/failed)
- NodeRegistry: online/degraded/stale/offline über Schwellen, UI-Kategorien
  discovered/paired/unknown/incompatible/offline, Doppel-Node-ID blockiert,
  IP-Wechsel erhaelt node_id (§6.3, §6.5)
- Pairing: PIN (TTL 120s, Versuchslimit), Fingerprint (SHA-256 gruppiert),
  Token nur als Hash, Scopes read/control/content_sync/admin, Ablauf +
  sofortiger Widerruf (§6.3, §27.1, ADR-0010)
- Discovery-Modell: _hmsmedia._tcp.local. TXT ohne Secrets, Capability-
  Digest, persistente manuelle Fallback-Liste (ADR-0009)
- ADR-0009 (mDNS + Fallback) und ADR-0010 (Paarung) dokumentiert
- 25 Unit-Tests; Gesamtsuite 183 Tests gruen, Ruff gruen

pyproject.toml

@@ -31,6 +31,7 @@ packages = [
     "packages/capabilities/hms_capabilities",
     "packages/plugin_sdk/hms_plugin_sdk",
     "packages/persistence/hms_persistence",
+    "packages/cluster/hms_cluster",
     "apps/renderer/hms_renderer",
     "apps/control_server/hms_control_server",
     "apps/launcher/hms_launcher",