refactor(health): move ICentralHealthAggregator and SiteHealthState to Commons (ScadaBridge#71)

Interface goes to Commons.Interfaces.Services and the state record to
Commons.Messages.Health, so CentralCommunicationActor no longer needs the
HealthMonitoring namespace. Implementation stays in HealthMonitoring.

Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV

docs/components/HealthMonitoring.md

@@ -10,7 +10,7 @@ The component code lives in `src/ZB.MOM.WW.ScadaBridge.HealthMonitoring/`:
 
 - `SiteHealthCollector` / `ISiteHealthCollector` — the site-side thread-safe accumulator that other site subsystems push metrics into. Script Actors, Alarm Actors, DCL connection actors, and the Audit Log bridge all call into this singleton.
 - `HealthReportSender` — a `BackgroundService` that ticks every `ReportInterval` (30 s), atomically drains the collector into a `SiteHealthReport`, stamps a monotonic sequence number, and fires it to central over `IHealthReportTransport` (Akka Tell, fire-and-forget). Only the active node sends — the standby runs the loop but skips the send.
-- `CentralHealthAggregator` / `ICentralHealthAggregator` — the central-side `BackgroundService` and in-memory store. Receives `SiteHealthReport` messages, applies them atomically via compare-and-swap on `SiteHealthState` records, and runs a periodic offline-detection sweep.
+- `CentralHealthAggregator` / `ICentralHealthAggregator` — the central-side `BackgroundService` and in-memory store. Receives `SiteHealthReport` messages, applies them atomically via compare-and-swap on `SiteHealthState` records, and runs a periodic offline-detection sweep. The contract types `ICentralHealthAggregator` (`Commons.Interfaces.Services`) and `SiteHealthState` (`Commons.Messages.Health`) live in Commons so consumers (e.g. `CentralCommunicationActor`) need not reference this project for them; the implementation stays here.
 - `CentralHealthReportLoop` — central-only counterpart to `HealthReportSender`: generates a synthetic `SiteHealthReport` for the central cluster itself (site ID `$central`) so central appears as a first-class card on `/monitoring/health`. Only the Primary (leader) node generates reports.
 - `SiteHealthState` — immutable record holding the latest report, last-heartbeat timestamp, sequence number, and online/offline flag for one site. Handed directly to UI callers; never torn because the aggregator swaps it atomically.
 

src/ZB.MOM.WW.ScadaBridge.AuditLog/Central/IAuditCentralHealthSnapshot.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.AuditLog.Payload;
 
 namespace ZB.MOM.WW.ScadaBridge.AuditLog.Central;

src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Monitoring/Health.razor

@@ -1,5 +1,7 @@
 @page "/monitoring/health"
 @attribute [Authorize]
+@using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services
+@using ZB.MOM.WW.ScadaBridge.Commons.Messages.Health
 @using ZB.MOM.WW.ScadaBridge.CentralUI.Components.Health
 @using ZB.MOM.WW.ScadaBridge.CentralUI.Services
 @using ZB.MOM.WW.ScadaBridge.Commons.Types

src/ZB.MOM.WW.ScadaBridge.CentralUI/ServiceCollectionExtensions.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Microsoft.AspNetCore.Components.Authorization;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Options;

src/ZB.MOM.WW.ScadaBridge.CentralUI/Services/AuditLogQueryService.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Microsoft.AspNetCore.Components.Authorization;
 using ZB.MOM.WW.ScadaBridge.CentralUI.Auth;
 using ZB.MOM.WW.ScadaBridge.Security;

src/ZB.MOM.WW.ScadaBridge.CentralUI/Services/ConnectionHealthQueryService.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
 using ZB.MOM.WW.ScadaBridge.HealthMonitoring;

src/ZB.MOM.WW.ScadaBridge.CentralUI/Services/IAuditLogQueryService.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Types;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Audit;
 

src/ZB.MOM.WW.ScadaBridge.CentralUI/Services/IConnectionHealthQueryService.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
 
 namespace ZB.MOM.WW.ScadaBridge.CentralUI.Services;

src/ZB.MOM.WW.ScadaBridge.Commons/Interfaces/Repositories/IAuditLogRepository.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.Audit;
 using ZB.MOM.WW.ScadaBridge.Commons.Types;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Audit;

src/ZB.MOM.WW.ScadaBridge.Commons/Interfaces/Services/ICentralHealthAggregator.cs

@@ -1,6 +1,6 @@
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Health;
 
-namespace ZB.MOM.WW.ScadaBridge.HealthMonitoring;
+namespace ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 
 /// <summary>
 /// Interface for central-side health aggregation.
@@ -21,7 +21,7 @@ public interface ICentralHealthAggregator
     /// cadence is owned by the Cluster Infrastructure / <c>SiteCommunicationActor</c>
     /// (the application-level heartbeat to central, sent every
     /// <c>CommunicationOptions.TransportHeartbeatInterval</c> — 5s by default);
-    /// the 60s <see cref="HealthMonitoringOptions.OfflineTimeout"/> therefore
+    /// the 60s <c>HealthMonitoringOptions.OfflineTimeout</c> therefore
     /// tolerates several missed heartbeats. A heartbeat for a site with no
     /// aggregator state yet (e.g. just after a central restart/failover)
     /// registers that site as online with no

src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Health/SiteHealthState.cs

@@ -1,6 +1,4 @@
-using ZB.MOM.WW.ScadaBridge.Commons.Messages.Health;
+namespace ZB.MOM.WW.ScadaBridge.Commons.Messages.Health;
-
-namespace ZB.MOM.WW.ScadaBridge.HealthMonitoring;
 
 /// <summary>
 /// In-memory state for a single site's health, stored by the central aggregator.
@@ -59,7 +57,7 @@ public sealed record SiteHealthState
     /// <summary>
     /// Gets a value indicating whether the site is online (heartbeats still
     /// arriving) but has sent no full <see cref="SiteHealthReport"/> within
-    /// <see cref="HealthMonitoringOptions.MetricsStaleTimeout"/>. This is a signal
+    /// <c>HealthMonitoringOptions.MetricsStaleTimeout</c>. This is a signal
     /// <em>distinct</em> from liveness: a site whose HealthReportSender died keeps
     /// heartbeating and would otherwise show "online with frozen metrics forever".
     /// Cleared whenever a fresh report is processed. Heartbeats never set or clear
@@ -69,12 +67,12 @@ public sealed record SiteHealthState
 
     /// <summary>
     /// Gets the instant this site's LocalDb replication oplog backlog first rose above
-    /// <see cref="HealthMonitoringOptions.LocalDbBacklogThreshold"/> and stayed there, or
+    /// <c>HealthMonitoringOptions.LocalDbBacklogThreshold</c> and stayed there, or
     /// <c>null</c> if the backlog is not currently above it (register row 33).
     /// </summary>
     /// <remarks>
     /// The anchor for the *sustained* backlog badge: the badge shows only once
-    /// <see cref="HealthMonitoringOptions.LocalDbBacklogSustainedFor"/> has elapsed since this
+    /// <c>HealthMonitoringOptions.LocalDbBacklogSustainedFor</c> has elapsed since this
     /// instant. Holding a start time rather than a boolean is what makes the signal survive the
     /// expected daily purge burst — that spike raises the backlog for a drain's worth of
     /// reports and then clears this back to null, never reaching the dwell.

src/ZB.MOM.WW.ScadaBridge.Communication/Actors/CentralCommunicationActor.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Akka.Actor;
 using Akka.Cluster.Tools.PublishSubscribe;
 using Akka.Event;
@@ -10,7 +11,6 @@ using ZB.MOM.WW.ScadaBridge.Commons.Messages.Communication;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Deployment;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Health;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Notification;
-using ZB.MOM.WW.ScadaBridge.HealthMonitoring;
 
 namespace ZB.MOM.WW.ScadaBridge.Communication.Actors;
 

src/ZB.MOM.WW.ScadaBridge.Communication/Grpc/CentralControlGrpcService.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Akka.Actor;
 using Google.Protobuf.WellKnownTypes;
 using Grpc.Core;

src/ZB.MOM.WW.ScadaBridge.HealthMonitoring/CentralHealthAggregator.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using System.Collections.Concurrent;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;

src/ZB.MOM.WW.ScadaBridge.HealthMonitoring/CentralHealthReportLoop.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;

src/ZB.MOM.WW.ScadaBridge.HealthMonitoring/Kpi/CentralHealthAuditBacklogProvider.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Kpi;
 
 namespace ZB.MOM.WW.ScadaBridge.HealthMonitoring.Kpi;

src/ZB.MOM.WW.ScadaBridge.HealthMonitoring/Kpi/SiteHealthKpiSampleSource.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Entities.Kpi;
 using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Kpi;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;

src/ZB.MOM.WW.ScadaBridge.HealthMonitoring/ServiceCollectionExtensions.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Hosting;

tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Pages/HealthPageTests.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using System.Security.Claims;
 using ZB.MOM.WW.ScadaBridge.Security;
 using Akka.Actor;

tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Services/AuditLogQueryServiceTests.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Diagnostics;
 using Microsoft.Extensions.DependencyInjection;

tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Services/AuditTreeScopeTests.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using System.Security.Claims;
 using Microsoft.AspNetCore.Components.Authorization;
 using Microsoft.Extensions.DependencyInjection;

tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Services/ConnectionHealthQueryServiceTests.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using NSubstitute;
 using ZB.MOM.WW.ScadaBridge.CentralUI.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Entities.Sites;

tests/ZB.MOM.WW.ScadaBridge.Communication.Tests/CentralCommunicationActorClientLifecycleTests.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Akka.Actor;
 using Akka.TestKit.Xunit2;
 using Microsoft.Extensions.DependencyInjection;

tests/ZB.MOM.WW.ScadaBridge.Communication.Tests/CentralCommunicationActorTests.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Akka.Actor;
 using Akka.TestKit.Xunit2;
 using Microsoft.Extensions.DependencyInjection;

tests/ZB.MOM.WW.ScadaBridge.Communication.Tests/HealthReportAckTests.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Akka.Actor;
 using Akka.TestKit.Xunit2;
 using Microsoft.Extensions.DependencyInjection;

tests/ZB.MOM.WW.ScadaBridge.HealthMonitoring.Tests/CentralHealthReportLoopTests.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Options;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Health;

tests/ZB.MOM.WW.ScadaBridge.HealthMonitoring.Tests/Kpi/CentralHealthAuditBacklogProviderTests.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Health;
 using ZB.MOM.WW.ScadaBridge.Commons.Types;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;

tests/ZB.MOM.WW.ScadaBridge.HealthMonitoring.Tests/Kpi/SiteHealthKpiSampleSourceTests.cs

@@ -1,3 +1,4 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Entities.Kpi;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Health;
 using ZB.MOM.WW.ScadaBridge.Commons.Types;