fix(hub): mgmt_plane_healed alerts on the FIRST auto-heal (TASK G1) — v0.34.1

A heal marker is an event, not a baseline: construction seeds pre-existing markers
(startup false-alarm guard) but a newly-observed marker now raises the warning, so
the first auto-heal surfaces (matches the live drill). Added tests for both halves.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PSK5g6qYLknKj8u3QAFEr6

manifests/hub.yaml

@@ -126,7 +126,7 @@ spec:
     spec:
       containers:
         - name: hub
-          image: gitea.dooplex.hu/admin/felhom-hub:0.34.0
+          image: gitea.dooplex.hu/admin/felhom-hub:0.34.1
           ports:
             - containerPort: 8080
               name: http