refactor(fleet): #542 delete the dead fleet-status chain (broadcaster, SignalR bridge, hub, messages)

#542 filed FleetStatusBroadcaster as blind to site nodes since the Phase 6 per-cluster mesh
split: it derives "the fleet" from central's own Akka gossip ring, which after the split is
just central's own pair. Scoping the cross-mesh rewrite found the deeper truth — the whole
chain is dead end to end, so this deletes it rather than reviving it.

  - Zero consumers. FleetStatusBroadcaster published FleetStatusChanged on the DPS
    "fleet-status" topic; FleetStatusSignalRBridge forwarded it to FleetStatusHub
    ("/hubs/fleet-status"); nothing anywhere connected. The AdminUI bans self-connecting
    HubConnections, no browser JS subscribes, and /fleet (Fleet.razor) reads
    NodeDeploymentState from the ConfigDb plus IClusterRoleInfo on a 5 s poll instead.
  - Its second input never existed. DriverHostStatusHeartbeat had no production sender —
    only the broadcaster's own test told it — so CurrentRevision was always null and the
    30 s staleness -> Degraded flip could never fire.
  - Post-Phase-6 DPS is pair-local, so even the central-only view it did produce was an
    accident of topology rather than a design.

The fleet visibility that actually works is unchanged and already cross-mesh-correct:
/fleet over NodeDeploymentState, and the four Phase 5 per-node telemetry dials.

Precedent for deleting inert machinery rather than activating it: #522 (driver stability
tiers), #507 (discovered-node injection), #525 (GetMemoryFootprint).

Deleted: FleetStatusBroadcaster (+ its nested DriverHostStatusHeartbeat), its admin
singleton registration and FleetStatusBroadcasterKey, FleetStatusSignalRBridge and its
key, FleetStatusHub and its route mapping, and the FleetStatusChanged / FleetNodeStatus /
FleetNodeHealth messages. Both Fleet/ directories survive — ControlPlane keeps
ClusterNodeAddressReconciler, Commons keeps GetDiagnostics. Docs swept where they claimed
a fleet-status channel exists (Telemetry.md's Phase 5 non-migrated channels,
Configuration.md, CLAUDE.md); completed-program plan docs under docs/plans and docs/v2 are
left as the historical record they are.

Build 0 errors, 868 warnings — byte-identical to master's rebuild baseline.
ControlPlane.Tests 231/231, AdminUI.Tests 1109/1109.

Claude-Session: https://claude.ai/code/session_014WNM4vjoVksyyBraTXSZE1

CLAUDE.md

@@ -509,11 +509,13 @@ touching it:
 - **Deferred, with reasons (do not read "seven observability topics" from the program sketch as the
   delivered scope):** `redundancy-state` stays on DPS in every mode (pair-local, built from
   `Cluster.State`, drives ServiceLevel + the Primary gate — genuinely mesh-bound by design, not an
-  observability panel); `fleet-status` is central-internal (`FleetStatusBroadcaster` builds it from
+  observability panel); `deployment-acks` already rides the Phase 2 gRPC command transport
-  the admin node's own membership events, `Fleet.razor` polls the Config DB and ignores the feed —
-  never a node→central stream); `deployment-acks` already rides the Phase 2 gRPC command transport
   (`MeshTransport:Mode=Grpc`, `CentralCommandService.ReportApply`) as a command-plane reply, not
-  telemetry.
+  telemetry. A third, `fleet-status`, was **DELETED** rather than deferred (2026-08-06, Gitea #542):
+  `FleetStatusBroadcaster` → DPS → SignalR bridge → `FleetStatusHub` had **zero clients end to end**
+  (no browser JS, no `HubConnection` — `/fleet` polls `NodeDeploymentState` in the Config DB), its
+  `DriverHostStatusHeartbeat` input had no production sender, and Phase 6 left its "fleet" as just
+  central's own pair. Fleet visibility is `/fleet` + the four per-node telemetry dials above.
 - **The node ALWAYS hosts and ALWAYS double-publishes, in both modes.** Every publish seam emits
   into a node-local `ITelemetryLocalHub` **and** still publishes DPS, unconditionally; the gRPC
   server binds whenever `Telemetry:GrpcListenPort > 0`, independent of `Telemetry:Mode`. Only

docs/Configuration.md

@@ -273,11 +273,12 @@ discipline as `MeshTransport:Mode` and `ConfigSource:Mode`.
 otherwise) — enforced by `TelemetryOptionsValidator`. **`Grpc` mode on either side requires a
 non-empty `ApiKey`** — fail-closed, same as `ConfigServe`/`LocalDb:Replication`.
 
-**Three DPS observability topics stay out of scope for this transport, on purpose:**
+**Two DPS observability topics stay out of scope for this transport, on purpose:**
 `redundancy-state` (pair-local, built from `Cluster.State`, stays on DPS in both modes — see
-[`Redundancy.md`](Redundancy.md#command-transport-centralnode)), `fleet-status` (central-internal;
+[`Redundancy.md`](Redundancy.md#command-transport-centralnode)) and `deployment-acks` (already rides
-`Fleet.razor` polls the Config DB, not any stream), and `deployment-acks` (already rides the Phase 2
+the Phase 2 gRPC command transport, `CentralCommandService.ReportApply`, as a command-plane reply).
-gRPC command transport, `CentralCommandService.ReportApply`, as a command-plane reply). See
+A third, `fleet-status`, was **deleted** rather than deferred (2026-08-06, Gitea #542 — it had no
+client end to end; `Fleet.razor` polls the Config DB). See
 [`docs/Telemetry.md`](Telemetry.md) for the full architecture, the reconnect/generation-stamped
 dialer story, and the rationale for the node-hosts/central-dials inversion.
 

docs/Telemetry.md

@@ -78,7 +78,6 @@ What actually changes per mode, precisely:
     `IDriverStatusSnapshotStore`, `IDriverResilienceStatusStore`).
 - **The AdminUI panels themselves are untouched.** `/alerts`, `/script-log`, and the `/hosts`
   driver table all read from the same sinks in both modes — only the sinks' upstream feed swaps.
-  The `fleet-status` bridge (out of Phase 5 scope — see below) stays on DPS in both modes.
 
 Because hosting is unconditional and both ingest paths are always compiled in, a fleet can be
 flipped node-by-node and central-by-central with no coordination window where telemetry is lost —
@@ -130,10 +129,10 @@ Three things to know before touching it:
 and no reader — the only reference in the repo is its DbSet declaration — while the live data reaches
 the AdminUI over the `driver-resilience-status` channel above. Keep-or-delete is Gitea **#524**.
 
-## The three deferred channels (NOT migrated in Phase 5 — do not read this as "seven done")
+## The three non-migrated channels (NOT migrated in Phase 5 — do not read this as "seven done")
 
 The program sketch originally named seven observability topics for Phase 5. Three were scoped out,
-each for a distinct, settled reason:
+each for a distinct, settled reason — and one of those three has since been deleted outright:
 
 - **`redundancy-state`** — bidirectional, built directly from `Cluster.State`, and **pair-local**:
   it drives ServiceLevel and the Primary data-plane gate, consumed in-process by
@@ -143,11 +142,17 @@ each for a distinct, settled reason:
   in-mesh. Central's *display* of each pair's redundancy state is a Phase 6 cross-mesh concern
   (a future observability channel, once central no longer shares gossip with any site pair), not a
   Phase 5 telemetry-panel migration.
-- **`fleet-status`** — **central-internal**, not a node→central stream at all. The admin singleton
+- **`fleet-status`** — **DELETED, 2026-08-06, Gitea #542.** There is no `fleet-status` channel any
-  `FleetStatusBroadcaster` builds it from the admin node's own cluster membership/reachability/
+  more, on DPS or anywhere else. It was central-internal rather than a node→central stream: the
-  leader events, and `Fleet.razor` **polls the Config DB** and ignores the feed entirely. There is
+  admin singleton `FleetStatusBroadcaster` built it from the admin node's own cluster membership/
-  nothing here for a per-node gRPC stream to carry. Revisit in Phase 6, once central genuinely
+  reachability/leader events and published to a SignalR hub that **no client anywhere ever
-  loses gossip visibility of site nodes and needs another way to know a pair's membership.
+  connected to** — `Fleet.razor` polls `NodeDeploymentState` in the Config DB and always ignored
+  the feed. Its second input, `DriverHostStatusHeartbeat`, had no production sender either. Phase 6
+  then made the central-only view wrong as well (central's gossip ring is its own pair). The whole
+  chain — broadcaster, singleton registration, DPS topic, SignalR bridge, `FleetStatusHub`, and the
+  `FleetStatusChanged`/`FleetNodeStatus` messages — was removed rather than rewritten cross-mesh.
+  Fleet visibility that does work today: `/fleet` over `NodeDeploymentState`, and the four Phase 5
+  telemetry channels above, which are per-node dials and therefore already mesh-independent.
 - **`deployment-acks`** — already migrated, but onto a different transport: it rides the Phase 2
   gRPC command transport (`MeshTransport:Mode=Grpc`, `CentralCommandService.ReportApply`) as a
   command-plane reply, not an observability broadcast. It was never a Phase 5 candidate.

src/Core/ZB.MOM.WW.OtOpcUa.Commons/Messages/Admin/StartDeploymentResult.cs

@@ -13,7 +13,7 @@ public enum StartDeploymentOutcome
 /// <summary>
 /// Reply from the <c>AdminOperationsActor</c> singleton. <c>Accepted</c> means the snapshot
 /// was sealed and a <c>Deployment</c> row was created; the in-flight deployment can be
-/// tracked through fleet-status broadcasts.
+/// tracked through the per-node <c>NodeDeploymentState</c> rows the AdminUI's /fleet page reads.
 /// </summary>
 public sealed record StartDeploymentResult(
     StartDeploymentOutcome Outcome,

src/Core/ZB.MOM.WW.OtOpcUa.Commons/Messages/Fleet/FleetStatusChanged.cs

@@ -1,21 +0,0 @@
-using ZB.MOM.WW.OtOpcUa.Commons.Types;
-
-namespace ZB.MOM.WW.OtOpcUa.Commons.Messages.Fleet;
-
-public enum FleetNodeHealth { Healthy, Degraded, Unreachable }
-
-public sealed record FleetNodeStatus(
-    NodeId NodeId,
-    FleetNodeHealth Health,
-    RevisionHash? CurrentRevision,
-    DateTime LastSeenUtc);
-
-/// <summary>
-/// Periodic fleet-wide status broadcast pushed by <c>FleetStatusBroadcaster</c> to admin UI
-/// subscribers via SignalR.
-/// </summary>
-public sealed record FleetStatusChanged(
-    IReadOnlyList<FleetNodeStatus> Nodes,
-    DeploymentId? CurrentDeployment,
-    DateTime AsOfUtc,
-    CorrelationId CorrelationId);

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Hubs/AlertSignalRBridge.cs

@@ -9,8 +9,7 @@ namespace ZB.MOM.WW.OtOpcUa.AdminUI.Hubs;
 /// <summary>
 /// Akka actor that subscribes to the <c>alerts</c> DistributedPubSub topic and forwards each
 /// <see cref="AlarmTransitionEvent"/> to every SignalR client connected to <see cref="AlertHub"/>.
-/// Mirrors <c>FleetStatusSignalRBridge</c>'s design — one bridge per admin node, hub fan-out is
+/// One bridge per admin node — hub fan-out is per-node, so no cluster-singleton is needed.
-/// per-node, no cluster-singleton needed.
 /// </summary>
 public sealed class AlertSignalRBridge : ReceiveActor
 {

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Hubs/FleetStatusHub.cs

@@ -1,19 +0,0 @@
-using Microsoft.AspNetCore.Authorization;
-using Microsoft.AspNetCore.SignalR;
-using ZB.MOM.WW.OtOpcUa.Commons.Messages.Fleet;
-
-namespace ZB.MOM.WW.OtOpcUa.AdminUI.Hubs;
-
-/// <summary>
-/// Browser-facing fleet-status push channel. Subscribers receive <see cref="FleetStatusChanged"/>
-/// snapshots whenever the admin-role <c>FleetStatusBroadcaster</c> publishes a diff.
-///
-/// Server pushes fleet-status updates to connected clients via <c>FleetStatusSignalRBridge</c>
-/// (DistributedPubSub 'fleet-status' → <c>IHubContext&lt;FleetStatusHub&gt;</c>).
-/// </summary>
-[Authorize]
-public sealed class FleetStatusHub : Hub
-{
-    public const string Endpoint = "/hubs/fleet-status";
-    public const string MethodName = "fleetStatusChanged";
-}

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Hubs/FleetStatusSignalRBridge.cs

@@ -1,58 +0,0 @@
-using Akka.Actor;
-using Akka.Cluster.Tools.PublishSubscribe;
-using Akka.Event;
-using Microsoft.AspNetCore.SignalR;
-using ZB.MOM.WW.OtOpcUa.Commons.Messages.Fleet;
-
-namespace ZB.MOM.WW.OtOpcUa.AdminUI.Hubs;
-
-/// <summary>
-/// Akka actor that subscribes to the <c>fleet-status</c> DistributedPubSub topic and forwards
-/// every <see cref="FleetStatusChanged"/> snapshot to all SignalR clients connected to
-/// <see cref="FleetStatusHub"/>. Spawned on admin-role nodes by
-/// <c>AddOtOpcUaSignalRBridges</c>.
-///
-/// The bridge runs locally on each admin node — every node that hosts the hub also forwards
-/// snapshots to its own connected clients. That keeps the hub-to-actor wiring simple (no
-/// cluster-singleton coordination needed) at the cost of duplicated DPS subscriptions on
-/// multi-admin deployments. Acceptable since the messages are small + the SignalR fan-out
-/// is per-node anyway.
-/// </summary>
-public sealed class FleetStatusSignalRBridge : ReceiveActor
-{
-    public const string TopicName = "fleet-status";
-
-    private readonly IHubContext<FleetStatusHub> _hub;
-    private readonly ILoggingAdapter _log = Context.GetLogger();
-
-    /// <summary>Creates actor props for a FleetStatusSignalRBridge with the specified hub context.</summary>
-    /// <param name="hub">The SignalR hub context.</param>
-    /// <returns>Props for creating a new FleetStatusSignalRBridge actor.</returns>
-    public static Props Props(IHubContext<FleetStatusHub> hub) =>
-        Akka.Actor.Props.Create(() => new FleetStatusSignalRBridge(hub));
-
-    /// <summary>Initializes a new instance of the FleetStatusSignalRBridge class.</summary>
-    /// <param name="hub">The SignalR hub context for sending messages to clients.</param>
-    public FleetStatusSignalRBridge(IHubContext<FleetStatusHub> hub)
-    {
-        _hub = hub;
-        ReceiveAsync<FleetStatusChanged>(ForwardAsync);
-        Receive<SubscribeAck>(_ => { /* DPS confirmation */ });
-    }
-
-    /// <inheritdoc />
-    protected override void PreStart() =>
-        DistributedPubSub.Get(Context.System).Mediator.Tell(new Subscribe(TopicName, Self));
-
-    private async Task ForwardAsync(FleetStatusChanged msg)
-    {
-        try
-        {
-            await _hub.Clients.All.SendAsync(FleetStatusHub.MethodName, msg);
-        }
-        catch (Exception ex)
-        {
-            _log.Warning(ex, "FleetStatusSignalRBridge: SignalR push failed (count={Count})", msg.Nodes.Count);
-        }
-    }
-}

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Hubs/HubRouteBuilderExtensions.cs

@@ -13,7 +13,6 @@ public static class HubRouteBuilderExtensions
     /// <returns>The same endpoint route builder, for chaining.</returns>
     public static IEndpointRouteBuilder MapOtOpcUaHubs(this IEndpointRouteBuilder app)
     {
-        app.MapHub<FleetStatusHub>(FleetStatusHub.Endpoint);
         app.MapHub<AlertHub>(AlertHub.Endpoint);
         app.MapHub<ScriptLogHub>(ScriptLogHub.Endpoint);
         app.MapHub<DriverStatusHub>(DriverStatusHub.Endpoint);

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Hubs/HubServiceCollectionExtensions.cs

@@ -14,7 +14,6 @@ namespace ZB.MOM.WW.OtOpcUa.AdminUI.Hubs;
 
 public static class HubServiceCollectionExtensions
 {
-    public const string FleetStatusSignalRBridgeName = "fleet-status-signalr-bridge";
     public const string AlertSignalRBridgeName = "alert-signalr-bridge";
     public const string ScriptLogSignalRBridgeName = "script-log-signalr-bridge";
     public const string DriverStatusSignalRBridgeName = "driver-status-signalr-bridge";
@@ -44,8 +43,8 @@ public static class HubServiceCollectionExtensions
 
     /// <summary>
     /// Spawns the SignalR bridge actors that forward DPS messages to browser-facing SignalR
-    /// hubs: <c>fleet-status</c> → <see cref="FleetStatusHub"/>, <c>alerts</c> →
+    /// hubs: <c>alerts</c> → <see cref="AlertHub"/>, <c>script-logs</c> →
-    /// <see cref="AlertHub"/>, <c>script-logs</c> → <see cref="ScriptLogHub"/>.
+    /// <see cref="ScriptLogHub"/>, <c>driver-health</c> → <see cref="DriverStatusHub"/>.
     ///
     /// Call inside the admin-role configurator on the shared <see cref="AkkaConfigurationBuilder"/>:
     /// <code>
@@ -62,12 +61,6 @@ public static class HubServiceCollectionExtensions
     {
         builder.WithActors((system, registry, resolver) =>
         {
-            // Fleet-status always stays on DPS in both modes (deferred / out of Phase 5 scope) — it is
-            // never gated by the telemetry dark switch.
-            var fleetHub = resolver.GetService<IHubContext<FleetStatusHub>>();
-            var fleetBridge = system.ActorOf(FleetStatusSignalRBridge.Props(fleetHub), FleetStatusSignalRBridgeName);
-            registry.Register<FleetStatusSignalRBridgeKey>(fleetBridge);
-
             // The four telemetry sinks are registered identically in both modes; only the upstream that
             // feeds them swaps (DPS bridges vs. the gRPC dial supervisor). Resolve them once, above the
             // branch, so both paths feed the SAME singletons the Blazor panels read.
@@ -131,7 +124,6 @@ public static class HubServiceCollectionExtensions
 }
 
 /// <summary>Marker keys for <see cref="ActorRegistry"/> lookup of the SignalR bridge actors.</summary>
-public sealed class FleetStatusSignalRBridgeKey { }
 public sealed class AlertSignalRBridgeKey { }
 public sealed class ScriptLogSignalRBridgeKey { }
 public sealed class DriverStatusSignalRBridgeKey { }

src/Server/ZB.MOM.WW.OtOpcUa.ControlPlane/Fleet/FleetStatusBroadcaster.cs

@@ -1,168 +0,0 @@
-using Akka.Actor;
-using Akka.Cluster;
-using Akka.Cluster.Tools.PublishSubscribe;
-using Akka.Event;
-using ZB.MOM.WW.OtOpcUa.Commons.Messages.Fleet;
-using ZB.MOM.WW.OtOpcUa.Commons.Types;
-
-namespace ZB.MOM.WW.OtOpcUa.ControlPlane.Fleet;
-
-/// <summary>
-/// Admin-role cluster singleton that maintains an in-memory <see cref="FleetStatusChanged"/>
-/// snapshot from cluster membership + reachability events plus per-node heartbeats, and pushes
-/// diffs on the <c>fleet-status</c> DistributedPubSub topic. The SignalR hub layer
-/// subscribes to that topic and forwards to browser clients.
-///
-/// Heartbeat staleness: a node we haven't heard from in <see cref="HeartbeatTimeout"/> flips
-/// from <see cref="FleetNodeHealth.Healthy"/> to <see cref="FleetNodeHealth.Degraded"/>. A
-/// cluster <c>Unreachable</c> event flips it straight to <see cref="FleetNodeHealth.Unreachable"/>.
-/// </summary>
-public sealed class FleetStatusBroadcaster : ReceiveActor, IWithTimers
-{
-    public const string Topic = "fleet-status";
-    public static readonly TimeSpan BroadcastInterval = TimeSpan.FromSeconds(5);
-    public static readonly TimeSpan HeartbeatTimeout = TimeSpan.FromSeconds(30);
-
-    private readonly Akka.Cluster.Cluster _cluster;
-    private readonly Action<object> _broadcast;
-    private readonly ILoggingAdapter _log = Context.GetLogger();
-    private readonly Dictionary<NodeId, NodeRecord> _nodes = new();
-
-    /// <summary>Gets or sets the timer scheduler for this actor.</summary>
-    public ITimerScheduler Timers { get; set; } = null!;
-
-    /// <summary>
-    /// Per-node heartbeat carrying the node's currently-applied revision hash, sent by
-    /// <c>DriverHostActor</c> periodically.
-    /// </summary>
-    public sealed record DriverHostStatusHeartbeat(NodeId NodeId, RevisionHash? CurrentRevision);
-
-    /// <summary>Creates actor props for the fleet status broadcaster.</summary>
-    /// <param name="broadcast">Optional custom broadcast delegate; defaults to distributed pub-sub mediator.</param>
-    /// <returns>Props configured to create a FleetStatusBroadcaster.</returns>
-    public static Props Props(Action<object>? broadcast = null) =>
-        Akka.Actor.Props.Create(() => new FleetStatusBroadcaster(broadcast));
-
-    /// <summary>Initializes a new instance of the FleetStatusBroadcaster actor.</summary>
-    /// <param name="broadcast">Optional custom broadcast delegate; if null, uses distributed pub-sub mediator.</param>
-    public FleetStatusBroadcaster(Action<object>? broadcast = null)
-    {
-        _cluster = Akka.Cluster.Cluster.Get(Context.System);
-        _broadcast = broadcast ?? (msg =>
-            DistributedPubSub.Get(Context.System).Mediator.Tell(new Publish(Topic, msg)));
-
-        Receive<ClusterEvent.MemberUp>(e => OnMemberUp(e.Member));
-        Receive<ClusterEvent.MemberRemoved>(e => OnMemberRemoved(e.Member));
-        Receive<ClusterEvent.UnreachableMember>(e => OnUnreachable(e.Member));
-        Receive<ClusterEvent.ReachableMember>(e => OnReachable(e.Member));
-        Receive<ClusterEvent.LeaderChanged>(_ => PublishSnapshot());
-        Receive<ClusterEvent.RoleLeaderChanged>(_ => PublishSnapshot());
-        Receive<DriverHostStatusHeartbeat>(OnHeartbeat);
-        Receive<Tick>(_ => OnTick());
-    }
-
-    /// <inheritdoc />
-    protected override void PreStart()
-    {
-        _cluster.Subscribe(
-            Self,
-            ClusterEvent.InitialStateAsEvents,
-            typeof(ClusterEvent.IMemberEvent),
-            typeof(ClusterEvent.LeaderChanged),
-            typeof(ClusterEvent.RoleLeaderChanged),
-            typeof(ClusterEvent.ReachabilityEvent));
-        Timers.StartPeriodicTimer("tick", Tick.Instance, BroadcastInterval);
-    }
-
-    /// <inheritdoc />
-    protected override void PostStop() => _cluster.Unsubscribe(Self);
-
-    private void OnMemberUp(Member m)
-    {
-        if (!TryNode(m, out var nodeId)) return;
-        _nodes[nodeId] = _nodes.TryGetValue(nodeId, out var prev)
-            ? prev with { Health = FleetNodeHealth.Healthy, LastSeenUtc = DateTime.UtcNow }
-            : new NodeRecord(nodeId, FleetNodeHealth.Healthy, CurrentRevision: null, DateTime.UtcNow);
-        PublishSnapshot();
-    }
-
-    private void OnMemberRemoved(Member m)
-    {
-        if (!TryNode(m, out var nodeId)) return;
-        _nodes.Remove(nodeId);
-        PublishSnapshot();
-    }
-
-    private void OnUnreachable(Member m)
-    {
-        if (!TryNode(m, out var nodeId) || !_nodes.TryGetValue(nodeId, out var rec)) return;
-        _nodes[nodeId] = rec with { Health = FleetNodeHealth.Unreachable };
-        PublishSnapshot();
-    }
-
-    private void OnReachable(Member m)
-    {
-        if (!TryNode(m, out var nodeId) || !_nodes.TryGetValue(nodeId, out var rec)) return;
-        _nodes[nodeId] = rec with { Health = FleetNodeHealth.Healthy, LastSeenUtc = DateTime.UtcNow };
-        PublishSnapshot();
-    }
-
-    private void OnHeartbeat(DriverHostStatusHeartbeat hb)
-    {
-        var rec = _nodes.TryGetValue(hb.NodeId, out var prev)
-            ? prev with
-            {
-                CurrentRevision = hb.CurrentRevision,
-                LastSeenUtc = DateTime.UtcNow,
-                Health = prev.Health == FleetNodeHealth.Unreachable ? prev.Health : FleetNodeHealth.Healthy,
-            }
-            : new NodeRecord(hb.NodeId, FleetNodeHealth.Healthy, hb.CurrentRevision, DateTime.UtcNow);
-        _nodes[hb.NodeId] = rec;
-    }
-
-    /// <summary>
-    /// Periodic tick — flips heartbeat-stale nodes to <see cref="FleetNodeHealth.Degraded"/> and
-    /// rebroadcasts the snapshot regardless so SignalR subscribers always have a recent baseline.
-    /// </summary>
-    private void OnTick()
-    {
-        var stale = DateTime.UtcNow - HeartbeatTimeout;
-        var flippedCount = 0;
-        foreach (var kv in _nodes.ToList())
-        {
-            if (kv.Value.LastSeenUtc < stale && kv.Value.Health == FleetNodeHealth.Healthy)
-            {
-                _nodes[kv.Key] = kv.Value with { Health = FleetNodeHealth.Degraded };
-                flippedCount++;
-            }
-        }
-        if (flippedCount > 0) _log.Debug("FleetStatusBroadcaster flipped {Count} nodes to Degraded", flippedCount);
-        PublishSnapshot();
-    }
-
-    private void PublishSnapshot()
-    {
-        var statuses = _nodes.Values
-            .Select(r => new FleetNodeStatus(r.NodeId, r.Health, r.CurrentRevision, r.LastSeenUtc))
-            .ToList();
-        var msg = new FleetStatusChanged(statuses, CurrentDeployment: null, DateTime.UtcNow, CorrelationId.NewId());
-        _broadcast(msg);
-    }
-
-    private static bool TryNode(Member m, out NodeId nodeId)
-    {
-        nodeId = default;
-        var host = m.Address.Host;
-        if (string.IsNullOrWhiteSpace(host)) return false;
-        nodeId = NodeId.Parse(host);
-        return true;
-    }
-
-    private sealed record NodeRecord(NodeId NodeId, FleetNodeHealth Health, RevisionHash? CurrentRevision, DateTime LastSeenUtc);
-
-    public sealed class Tick
-    {
-        public static readonly Tick Instance = new();
-        private Tick() { }
-    }
-}

src/Server/ZB.MOM.WW.OtOpcUa.ControlPlane/ServiceCollectionExtensions.cs

@@ -26,12 +26,11 @@ public static class ServiceCollectionExtensions
     public const string ConfigPublishSingletonName = "config-publish";
     public const string AdminOperationsSingletonName = "admin-operations";
     public const string AuditWriterSingletonName = "audit-writer";
-    public const string FleetStatusSingletonName = "fleet-status";
     public const string RedundancyStateSingletonName = "redundancy-state";
     public const string ClusterNodeAddressReconcilerSingletonName = "cluster-node-address-reconciler";
 
     /// <summary>
-    /// Registers the admin-role cluster singletons on the AkkaConfigurationBuilder — five with
+    /// Registers the admin-role cluster singletons on the AkkaConfigurationBuilder — three with
     /// registry proxies, plus the address reconciler, which is proxy-less because nothing addresses it.
     /// Must be called against the same builder used by <c>AkkaHostedService</c> so the singletons
     /// share the host's ActorSystem.
@@ -139,10 +138,11 @@ public static class ServiceCollectionExtensions
             },
             singletonOptions);
 
-        builder.WithSingleton<FleetStatusBroadcasterKey>(
+        // Gitea #542 (2026-08-06): the fleet-status singleton is NO LONGER registered here — the
-            FleetStatusSingletonName,
+        // whole FleetStatusBroadcaster → DPS → SignalR bridge → FleetStatusHub chain was DELETED.
-            (system, registry, resolver) => FleetStatusBroadcaster.Props(),
+        // It had zero clients end-to-end (no browser JS, no HubConnection — /fleet reads
-            singletonOptions);
+        // NodeDeploymentState from the ConfigDb on a poll), its DriverHostStatusHeartbeat input had
+        // no production sender, and after mesh Phase 6 its "fleet" was only central's own pair.
 
         // Per-cluster mesh Phase 6: the redundancy-state singleton is NO LONGER registered here.
         // It was an admin-scoped, fleet-wide singleton — one Primary elected across the whole mesh.
@@ -253,7 +253,6 @@ public static class ServiceCollectionExtensions
 public sealed class ConfigPublishCoordinatorKey { }
 public sealed class AdminOperationsActorKey { }
 public sealed class AuditWriterActorKey { }
-public sealed class FleetStatusBroadcasterKey { }
 public sealed class RedundancyStateActorKey { }
 public sealed class ClusterNodeAddressReconcilerKey { }
 public sealed class CentralCommunicationActorKey { }

tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Hubs/TelemetryModeWiringTests.cs

@@ -16,12 +16,11 @@ namespace ZB.MOM.WW.OtOpcUa.AdminUI.Tests.Hubs;
 ///     Verifies the Phase 5 dark switch in <see cref="HubServiceCollectionExtensions.WithOtOpcUaSignalRBridges"/>:
 ///     <c>TelemetryDial:Mode = Dps</c> (default) spawns the four telemetry DPS bridge actors and NOT the
 ///     gRPC dial supervisor; <c>Grpc</c> spawns the dial supervisor and NONE of the four telemetry
-///     bridges. The fleet-status bridge (deferred / out of Phase 5 scope) is spawned in BOTH modes.
+///     bridges. The gate is proven on a real <see cref="ActorRegistry"/> from a started Akka host.
-///     The gate is proven on a real <see cref="ActorRegistry"/> from a started Akka host.
 /// </summary>
 public sealed class TelemetryModeWiringTests
 {
-    /// <summary>Dps mode: the four telemetry bridges + fleet bridge are registered; the dial supervisor is not.</summary>
+    /// <summary>Dps mode: the four telemetry bridges are registered; the dial supervisor is not.</summary>
     [Fact]
     public async Task Dps_mode_spawns_the_four_telemetry_bridges_and_not_the_dial_supervisor()
     {
@@ -31,7 +30,6 @@ public sealed class TelemetryModeWiringTests
         {
             var registry = host.Services.GetRequiredService<ActorRegistry>();
 
-            registry.TryGet<FleetStatusSignalRBridgeKey>(out _).ShouldBeTrue();
             registry.TryGet<AlertSignalRBridgeKey>(out _).ShouldBeTrue();
             registry.TryGet<ScriptLogSignalRBridgeKey>(out _).ShouldBeTrue();
             registry.TryGet<DriverStatusSignalRBridgeKey>(out _).ShouldBeTrue();
@@ -45,7 +43,7 @@ public sealed class TelemetryModeWiringTests
         }
     }
 
-    /// <summary>Grpc mode: the dial supervisor + fleet bridge are registered; none of the four telemetry bridges are.</summary>
+    /// <summary>Grpc mode: the dial supervisor is registered; none of the four telemetry bridges are.</summary>
     [Fact]
     public async Task Grpc_mode_spawns_the_dial_supervisor_and_none_of_the_four_telemetry_bridges()
     {
@@ -55,7 +53,6 @@ public sealed class TelemetryModeWiringTests
         {
             var registry = host.Services.GetRequiredService<ActorRegistry>();
 
-            registry.TryGet<FleetStatusSignalRBridgeKey>(out _).ShouldBeTrue();
             registry.TryGet<TelemetryDialSupervisorKey>(out _).ShouldBeTrue();
 
             registry.TryGet<AlertSignalRBridgeKey>(out _).ShouldBeFalse();

tests/Server/ZB.MOM.WW.OtOpcUa.ControlPlane.Tests/FleetStatusBroadcasterTests.cs

@@ -1,47 +0,0 @@
-using Akka.Actor;
-using Shouldly;
-using Xunit;
-using ZB.MOM.WW.OtOpcUa.Commons.Messages.Fleet;
-using ZB.MOM.WW.OtOpcUa.Commons.Types;
-using ZB.MOM.WW.OtOpcUa.ControlPlane.Fleet;
-using ZB.MOM.WW.OtOpcUa.ControlPlane.Tests.Harness;
-
-namespace ZB.MOM.WW.OtOpcUa.ControlPlane.Tests;
-
-public sealed class FleetStatusBroadcasterTests : ControlPlaneActorTestBase
-{
-    /// <summary>Verifies that the self member's join appears in the initial fleet status snapshot.</summary>
-    [Fact]
-    public void Self_member_up_lands_in_snapshot()
-    {
-        var probe = CreateTestProbe();
-        Sys.ActorOf(FleetStatusBroadcaster.Props(broadcast: msg => probe.Ref.Tell(msg)));
-
-        // The cluster self-joined in the harness — InitialStateAsEvents replays MemberUp for self.
-        var snapshot = probe.ExpectMsg<FleetStatusChanged>(TimeSpan.FromSeconds(5));
-        snapshot.Nodes.Count.ShouldBeGreaterThanOrEqualTo(1);
-        snapshot.Nodes.Any(n => n.Health == FleetNodeHealth.Healthy).ShouldBeTrue();
-    }
-
-    /// <summary>Verifies that heartbeat messages update the node revision in the next broadcast.</summary>
-    [Fact]
-    public void Heartbeat_updates_revision_in_next_snapshot()
-    {
-        var probe = CreateTestProbe();
-        var actor = Sys.ActorOf(FleetStatusBroadcaster.Props(broadcast: msg => probe.Ref.Tell(msg)));
-
-        // Drain the initial MemberUp snapshot.
-        probe.ExpectMsg<FleetStatusChanged>(TimeSpan.FromSeconds(5));
-
-        // Send a heartbeat for a node we know about (the self node from the cluster).
-        var selfHost = Akka.Cluster.Cluster.Get(Sys).SelfAddress.Host!;
-        var rev = RevisionHash.Parse(new string('c', 64));
-        actor.Tell(new FleetStatusBroadcaster.DriverHostStatusHeartbeat(NodeId.Parse(selfHost), rev));
-
-        // Wait for next periodic broadcast and assert the revision propagated.
-        var next = probe.FishForMessage<FleetStatusChanged>(
-            isMessage: m => m.Nodes.Any(n => n.CurrentRevision == rev),
-            max: TimeSpan.FromSeconds(10));
-        next.Nodes.Single(n => n.NodeId.Value == selfHost).CurrentRevision.ShouldBe(rev);
-    }
-}

tests/Server/ZB.MOM.WW.OtOpcUa.ControlPlane.Tests/RedundancyStateSingletonRehomeTests.cs

@@ -69,7 +69,7 @@ public sealed class RedundancyStateSingletonRehomeTests
 
         registry.TryGet<RedundancyStateActorKey>(out _).ShouldBeFalse(
             "the redundancy singleton was re-homed off the admin node onto every driver node (Phase 6)");
-        registry.TryGet<FleetStatusBroadcasterKey>(out _).ShouldBeTrue(
+        registry.TryGet<AuditWriterActorKey>(out _).ShouldBeTrue(
             "the remaining admin singletons must still register");
     }