refactor(mesh-phase4): retire EfAlarmConditionStateStore + drop dead ScriptedAlarmState table (Task 9)

Scripted-alarm condition state lives in LocalDb (Phase 4); the ConfigDb-backed
Ef store + ScriptedAlarmState table are now dead. Removes the test-harness Ef
fallback (a DB-backed node with no store now skips the alarm host), deletes the
store + entity + model config, and drops the table via migration.

Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Entities/ScriptedAlarmState.cs

@@ -1,65 +0,0 @@
-namespace ZB.MOM.WW.OtOpcUa.Configuration.Entities;
-
-/// <summary>
-///     Persistent runtime state for each scripted alarm. Survives process restart so
-///     operators don't re-ack and ack history survives for
-///     GxP / 21 CFR Part 11 compliance. Keyed on <c>ScriptedAlarmId</c> logically (not
-///     per-generation) because ack state follows the alarm's stable identity across
-///     generations — a Modified alarm keeps its ack history.
-/// </summary>
-/// <remarks>
-///     <para>
-///         <c>ActiveState</c> is deliberately NOT persisted — it rederives from the current
-///         predicate evaluation on startup. Only operator-supplied state (<see cref="AckedState"/>,
-///         <see cref="ConfirmedState"/>, <see cref="ShelvingState"/>) + audit trail persist.
-///     </para>
-///     <para>
-///         <see cref="CommentsJson"/> is an append-only JSON array of <c>{user, utc, text}</c>
-///         tuples — one per operator comment. Core.ScriptedAlarms' <c>AlarmConditionState.Comments</c>
-///         serializes directly into this column.
-///     </para>
-/// </remarks>
-public sealed class ScriptedAlarmState
-{
-    /// <summary>Logical FK — matches <see cref="ScriptedAlarm.ScriptedAlarmId"/>. One row per alarm identity.</summary>
-    public required string ScriptedAlarmId { get; set; }
-
-    /// <summary>Enabled/Disabled. Persists across restart.</summary>
-    public required string EnabledState { get; set; } = "Enabled";
-
-    /// <summary>Unacknowledged / Acknowledged.</summary>
-    public required string AckedState { get; set; } = "Unacknowledged";
-
-    /// <summary>Unconfirmed / Confirmed.</summary>
-    public required string ConfirmedState { get; set; } = "Unconfirmed";
-
-    /// <summary>Unshelved / OneShotShelved / TimedShelved.</summary>
-    public required string ShelvingState { get; set; } = "Unshelved";
-
-    /// <summary>When a TimedShelve expires — null if not shelved or OneShotShelved.</summary>
-    public DateTime? ShelvingExpiresUtc { get; set; }
-
-    /// <summary>User who last acknowledged. Null if never acked.</summary>
-    public string? LastAckUser { get; set; }
-
-    /// <summary>Operator-supplied ack comment. Null if no comment or never acked.</summary>
-    public string? LastAckComment { get; set; }
-
-    /// <summary>Gets or sets the UTC timestamp of the last acknowledgment.</summary>
-    public DateTime? LastAckUtc { get; set; }
-
-    /// <summary>User who last confirmed.</summary>
-    public string? LastConfirmUser { get; set; }
-
-    /// <summary>Gets or sets the operator-supplied confirm comment. Null if no comment or never confirmed.</summary>
-    public string? LastConfirmComment { get; set; }
-
-    /// <summary>Gets or sets the UTC timestamp of the last confirmation.</summary>
-    public DateTime? LastConfirmUtc { get; set; }
-
-    /// <summary>JSON array of operator comments, append-only (GxP audit).</summary>
-    public string CommentsJson { get; set; } = "[]";
-
-    /// <summary>Row write timestamp — tracks last state change.</summary>
-    public DateTime UpdatedAtUtc { get; set; }
-}

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/20260723183050_DropScriptedAlarmStateTable.cs

@@ -0,0 +1,47 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
+{
+    /// <inheritdoc />
+    public partial class DropScriptedAlarmStateTable : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "ScriptedAlarmState");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "ScriptedAlarmState",
+                columns: table => new
+                {
+                    ScriptedAlarmId = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: false),
+                    AckedState = table.Column<string>(type: "nvarchar(16)", maxLength: 16, nullable: false),
+                    CommentsJson = table.Column<string>(type: "nvarchar(max)", nullable: false),
+                    ConfirmedState = table.Column<string>(type: "nvarchar(16)", maxLength: 16, nullable: false),
+                    EnabledState = table.Column<string>(type: "nvarchar(16)", maxLength: 16, nullable: false),
+                    LastAckComment = table.Column<string>(type: "nvarchar(1024)", maxLength: 1024, nullable: true),
+                    LastAckUser = table.Column<string>(type: "nvarchar(128)", maxLength: 128, nullable: true),
+                    LastAckUtc = table.Column<DateTime>(type: "datetime2(3)", nullable: true),
+                    LastConfirmComment = table.Column<string>(type: "nvarchar(1024)", maxLength: 1024, nullable: true),
+                    LastConfirmUser = table.Column<string>(type: "nvarchar(128)", maxLength: 128, nullable: true),
+                    LastConfirmUtc = table.Column<DateTime>(type: "datetime2(3)", nullable: true),
+                    ShelvingExpiresUtc = table.Column<DateTime>(type: "datetime2(3)", nullable: true),
+                    ShelvingState = table.Column<string>(type: "nvarchar(16)", maxLength: 16, nullable: false),
+                    UpdatedAtUtc = table.Column<DateTime>(type: "datetime2(3)", nullable: false, defaultValueSql: "SYSUTCDATETIME()")
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_ScriptedAlarmState", x => x.ScriptedAlarmId);
+                    table.CheckConstraint("CK_ScriptedAlarmState_CommentsJson_IsJson", "ISJSON(CommentsJson) = 1");
+                });
+        }
+    }
+}

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/OtOpcUaConfigDbContextModelSnapshot.cs

@@ -1113,74 +1113,6 @@ namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
                         });
                 });
 
-            modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ScriptedAlarmState", b =>
-                {
-                    b.Property<string>("ScriptedAlarmId")
-                        .HasMaxLength(64)
-                        .HasColumnType("nvarchar(64)");
-
-                    b.Property<string>("AckedState")
-                        .IsRequired()
-                        .HasMaxLength(16)
-                        .HasColumnType("nvarchar(16)");
-
-                    b.Property<string>("CommentsJson")
-                        .IsRequired()
-                        .HasColumnType("nvarchar(max)");
-
-                    b.Property<string>("ConfirmedState")
-                        .IsRequired()
-                        .HasMaxLength(16)
-                        .HasColumnType("nvarchar(16)");
-
-                    b.Property<string>("EnabledState")
-                        .IsRequired()
-                        .HasMaxLength(16)
-                        .HasColumnType("nvarchar(16)");
-
-                    b.Property<string>("LastAckComment")
-                        .HasMaxLength(1024)
-                        .HasColumnType("nvarchar(1024)");
-
-                    b.Property<string>("LastAckUser")
-                        .HasMaxLength(128)
-                        .HasColumnType("nvarchar(128)");
-
-                    b.Property<DateTime?>("LastAckUtc")
-                        .HasColumnType("datetime2(3)");
-
-                    b.Property<string>("LastConfirmComment")
-                        .HasMaxLength(1024)
-                        .HasColumnType("nvarchar(1024)");
-
-                    b.Property<string>("LastConfirmUser")
-                        .HasMaxLength(128)
-                        .HasColumnType("nvarchar(128)");
-
-                    b.Property<DateTime?>("LastConfirmUtc")
-                        .HasColumnType("datetime2(3)");
-
-                    b.Property<DateTime?>("ShelvingExpiresUtc")
-                        .HasColumnType("datetime2(3)");
-
-                    b.Property<string>("ShelvingState")
-                        .IsRequired()
-                        .HasMaxLength(16)
-                        .HasColumnType("nvarchar(16)");
-
-                    b.Property<DateTime>("UpdatedAtUtc")
-                        .ValueGeneratedOnAdd()
-                        .HasColumnType("datetime2(3)")
-                        .HasDefaultValueSql("SYSUTCDATETIME()");
-
-                    b.HasKey("ScriptedAlarmId");
-
-                    b.ToTable("ScriptedAlarmState", null, t =>
-                        {
-                            t.HasCheckConstraint("CK_ScriptedAlarmState_CommentsJson_IsJson", "ISJSON(CommentsJson) = 1");
-                        });
-                });
-
             modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ServerCluster", b =>
                 {
                     b.Property<string>("ClusterId")

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/OtOpcUaConfigDbContext.cs

@@ -56,8 +56,6 @@ public sealed class OtOpcUaConfigDbContext(DbContextOptions<OtOpcUaConfigDbConte
     public DbSet<VirtualTag> VirtualTags => Set<VirtualTag>();
     /// <summary>Gets the DbSet of scripted alarms.</summary>
     public DbSet<ScriptedAlarm> ScriptedAlarms => Set<ScriptedAlarm>();
-    /// <summary>Gets the DbSet of scripted alarm states.</summary>
-    public DbSet<ScriptedAlarmState> ScriptedAlarmStates => Set<ScriptedAlarmState>();
 
     // v2 deploy-model tables (Phase 1 of the Akka + fused-hosting alignment).
     /// <summary>Gets the DbSet of deployments.</summary>
@@ -98,7 +96,6 @@ public sealed class OtOpcUaConfigDbContext(DbContextOptions<OtOpcUaConfigDbConte
         ConfigureScript(modelBuilder);
         ConfigureVirtualTag(modelBuilder);
         ConfigureScriptedAlarm(modelBuilder);
-        ConfigureScriptedAlarmState(modelBuilder);
         ConfigureDeployment(modelBuilder);
         ConfigureNodeDeploymentState(modelBuilder);
         ConfigureConfigEdit(modelBuilder);
@@ -716,34 +713,6 @@ public sealed class OtOpcUaConfigDbContext(DbContextOptions<OtOpcUaConfigDbConte
         });
     }
 
-    private static void ConfigureScriptedAlarmState(ModelBuilder modelBuilder)
-    {
-        modelBuilder.Entity<ScriptedAlarmState>(e =>
-        {
-            // Logical-id keyed (not generation-scoped) because ack state follows the alarm's
-            // stable identity across generations — Modified alarms keep their ack audit trail.
-            e.ToTable("ScriptedAlarmState", t =>
-            {
-                t.HasCheckConstraint("CK_ScriptedAlarmState_CommentsJson_IsJson", "ISJSON(CommentsJson) = 1");
-            });
-            e.HasKey(x => x.ScriptedAlarmId);
-            e.Property(x => x.ScriptedAlarmId).HasMaxLength(64);
-            e.Property(x => x.EnabledState).HasMaxLength(16);
-            e.Property(x => x.AckedState).HasMaxLength(16);
-            e.Property(x => x.ConfirmedState).HasMaxLength(16);
-            e.Property(x => x.ShelvingState).HasMaxLength(16);
-            e.Property(x => x.ShelvingExpiresUtc).HasColumnType("datetime2(3)");
-            e.Property(x => x.LastAckUser).HasMaxLength(128);
-            e.Property(x => x.LastAckComment).HasMaxLength(1024);
-            e.Property(x => x.LastAckUtc).HasColumnType("datetime2(3)");
-            e.Property(x => x.LastConfirmUser).HasMaxLength(128);
-            e.Property(x => x.LastConfirmComment).HasMaxLength(1024);
-            e.Property(x => x.LastConfirmUtc).HasColumnType("datetime2(3)");
-            e.Property(x => x.CommentsJson).HasColumnType("nvarchar(max)");
-            e.Property(x => x.UpdatedAtUtc).HasColumnType("datetime2(3)").HasDefaultValueSql("SYSUTCDATETIME()");
-        });
-    }
-
     private static void ConfigureDeployment(ModelBuilder modelBuilder)
     {
         modelBuilder.Entity<Deployment>(e =>

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs

@@ -113,9 +113,8 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     ///     Scripted-alarm condition-state store handed to the ScriptedAlarm engine, or
     ///     <see langword="null"/> when none was wired (per-cluster mesh Phase 4). On a driver-role node
     ///     this is the replicated LocalDb store (<c>LocalDbAlarmConditionStateStore</c>) so condition
-    ///     state survives without central SQL; when null the actor falls back to an
-    ///     <see cref="EfAlarmConditionStateStore"/> over <see cref="_dbFactory"/> (legacy admin/Direct +
-    ///     test harnesses), or — when there is no ConfigDb either — skips spawning the alarm host.
+    ///     state survives without central SQL; when null the actor skips spawning the alarm host (the
+    ///     ConfigDb-backed EF fallback was retired in Phase 4 Task 9).
     /// </summary>
     private readonly IAlarmStateStore? _alarmStateStore;
 
@@ -135,7 +134,6 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     private readonly IVirtualTagEvaluator _virtualTagEvaluator;
     private readonly IHistoryWriter _historyWriter;
     private readonly IActorRef? _virtualTagHostOverride;
-    private readonly ILoggerFactory _loggerFactory;
     private readonly ScriptRootLogger? _scriptRootLogger;
     private readonly IActorRef? _scriptedAlarmHostOverride;
     private readonly ILoggingAdapter _log = Context.GetLogger();
@@ -383,9 +381,8 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     /// VirtualTag host instead of spawning a real <see cref="VirtualTagHostActor"/> child, so tests
     /// can intercept the <see cref="VirtualTagHostActor.ApplyVirtualTags"/> message. Null in
     /// production (the real host is spawned).</param>
-    /// <param name="loggerFactory">Optional logger factory used to create the
-    /// <see cref="EfAlarmConditionStateStore"/>'s logger when spawning the ScriptedAlarm host;
-    /// defaults to <see cref="NullLoggerFactory"/> when not provided.</param>
+    /// <param name="loggerFactory">Retained for constructor-signature stability; unused since Phase 4
+    /// Task 9 retired the <c>EfAlarmConditionStateStore</c> fallback that consumed it. Defaults to null.</param>
     /// <param name="scriptRootLogger">Optional root script logger required to spawn the ScriptedAlarm
     /// host (the engine + its script logging hang off it). When null the ScriptedAlarm host is left
     /// unspawned — the graceful dev/None-deployment path.</param>
@@ -398,9 +395,8 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     /// <see cref="NullDriverCapabilityInvokerFactory"/> (pass-through) when not supplied.</param>
     /// <param name="alarmStateStore">Per-cluster mesh Phase 4: scripted-alarm condition-state store. On a
     /// driver-role node this is the replicated LocalDb store, so condition state persists with no
-    /// ConfigDb; null falls back to an <see cref="EfAlarmConditionStateStore"/> over
-    /// <paramref name="dbFactory"/> (legacy admin/Direct + test harnesses), or skips the alarm host when
-    /// there is no ConfigDb either. Defaults to null.</param>
+    /// ConfigDb; null skips spawning the alarm host (the ConfigDb-backed EF fallback was retired in
+    /// Phase 4 Task 9). Defaults to null.</param>
     /// <returns>The Akka.NET <see cref="Akka.Actor.Props"/> used to spawn this actor.</returns>
     public static Props Props(
         IDbContextFactory<OtOpcUaConfigDbContext>? dbFactory,
@@ -454,8 +450,8 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     /// for historized VirtualTag results; defaults to <see cref="NullHistoryWriter"/>.</param>
     /// <param name="virtualTagHostOverride">Test seam: when supplied, used as the VirtualTag host
     /// instead of spawning a real <see cref="VirtualTagHostActor"/> child.</param>
-    /// <param name="loggerFactory">Optional logger factory used to create the
-    /// <see cref="EfAlarmConditionStateStore"/>'s logger; defaults to <see cref="NullLoggerFactory"/>.</param>
+    /// <param name="loggerFactory">Retained for constructor-signature stability; unused since Phase 4
+    /// Task 9 retired the <c>EfAlarmConditionStateStore</c> fallback that consumed it. Defaults to null.</param>
     /// <param name="scriptRootLogger">Optional root script logger required to spawn the ScriptedAlarm
     /// host; when null the host is left unspawned.</param>
     /// <param name="scriptedAlarmHostOverride">Test seam: when supplied, used as the ScriptedAlarm host
@@ -471,9 +467,8 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     /// last-known-good configuration while central SQL is unreachable. Null on admin-only nodes and in
     /// tests that do not exercise the cache — caching is then simply skipped.</param>
     /// <param name="alarmStateStore">Per-cluster mesh Phase 4: scripted-alarm condition-state store. On a
-    /// driver-role node this is the replicated LocalDb store; null falls back to an
-    /// <see cref="EfAlarmConditionStateStore"/> over <paramref name="dbFactory"/>, or skips the alarm
-    /// host when there is no ConfigDb either.</param>
+    /// driver-role node this is the replicated LocalDb store; null skips spawning the alarm host (the
+    /// ConfigDb-backed EF fallback was retired in Phase 4 Task 9).</param>
     public DriverHostActor(
         IDbContextFactory<OtOpcUaConfigDbContext>? dbFactory,
         CommonsNodeId localNode,
@@ -517,7 +512,6 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
         _virtualTagEvaluator = virtualTagEvaluator ?? NullVirtualTagEvaluator.Instance;
         _historyWriter = historyWriter ?? NullHistoryWriter.Instance;
         _virtualTagHostOverride = virtualTagHostOverride;
-        _loggerFactory = loggerFactory ?? NullLoggerFactory.Instance;
         _scriptRootLogger = scriptRootLogger;
         _scriptedAlarmHostOverride = scriptedAlarmHostOverride;
 
@@ -597,9 +591,10 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     ///     <see cref="_scriptRootLogger"/> (the engine + its script logging hang off it); when either
     ///     is missing (legacy ControlPlane test harnesses, dev/None deployments) the host is left
     ///     null and ApplyScriptedAlarms becomes a no-op. The engine is built around a fresh
-    ///     <see cref="DependencyMuxTagUpstreamSource"/> + an <see cref="EfAlarmConditionStateStore"/>;
-    ///     the host (spawned as a child) owns + disposes the engine in its PostStop, so it stops with
-    ///     the driver host.
+    ///     <see cref="DependencyMuxTagUpstreamSource"/> + the wired <see cref="IAlarmStateStore"/> (the
+    ///     replicated <c>LocalDbAlarmConditionStateStore</c> on a driver-role node); when no store was
+    ///     wired the host is skipped. The host (spawned as a child) owns + disposes the engine in its
+    ///     PostStop, so it stops with the driver host.
     /// </summary>
     private void SpawnScriptedAlarmHost()
     {
@@ -617,30 +612,20 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
             return;
         }
 
-        // Per-cluster mesh Phase 4: prefer the wired condition-state store (the replicated LocalDb store
-        // on a driver-role node — it persists with no ConfigDb). Only when no store was wired do we fall
-        // back to the ConfigDb-backed EF store, and only if there IS a ConfigDb (legacy admin/Direct +
-        // test harnesses). A driver-only node has neither — nowhere to persist condition state — so it
-        // skips the alarm host outright rather than constructing an EF store over a null factory that
-        // would NRE the moment the engine touched it (mirrors the _opcUaPublishActor-null skip above).
-        IAlarmStateStore store;
-        if (_alarmStateStore is not null)
-        {
-            store = _alarmStateStore;
-        }
-        else if (_dbFactory is not null)
-        {
-            store = new EfAlarmConditionStateStore(
-                _dbFactory, _loggerFactory.CreateLogger<EfAlarmConditionStateStore>());
-        }
-        else
+        // Per-cluster mesh Phase 4: condition state lives in the wired store — the replicated LocalDb
+        // store on a driver-role node, which persists with no ConfigDb. The ConfigDb-backed EF fallback
+        // was retired (Task 9); when no store was wired there is nowhere to persist condition state, so
+        // we skip the alarm host outright rather than run the engine against a store it can never save to
+        // (mirrors the _opcUaPublishActor-null skip above).
+        if (_alarmStateStore is null)
         {
             _log.Debug(
-                "DriverHost {Node}: skipping ScriptedAlarm host spawn (no condition-state store and no ConfigDb)",
+                "DriverHost {Node}: skipping ScriptedAlarm host spawn (no condition-state store)",
                 _localNode);
             return;
         }
 
+        var store = _alarmStateStore;
         var upstream = new DependencyMuxTagUpstreamSource();
         var engine = new ScriptedAlarmEngine(
             upstream, store, new ScriptLoggerFactory(_scriptRootLogger.Logger), _scriptRootLogger.Logger);

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ScriptedAlarms/EfAlarmConditionStateStore.cs

@@ -1,240 +0,0 @@
-using System.Collections.Immutable;
-using System.Text.Json;
-using Microsoft.EntityFrameworkCore;
-using Microsoft.Extensions.Logging;
-using ZB.MOM.WW.OtOpcUa.Configuration;
-using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
-using ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms;
-
-namespace ZB.MOM.WW.OtOpcUa.Runtime.ScriptedAlarms;
-
-/// <summary>
-///     Production-side <see cref="IAlarmStateStore"/> backed by the
-///     <see cref="ScriptedAlarmState"/> table in the central config DB. This store maps the
-///     full Part 9 <see cref="AlarmConditionState"/> — Enabled / Acked / Confirmed / Shelving
-///     + the ack/confirm audit trail + operator comments.
-/// </summary>
-/// <remarks>
-///     <para>
-///         <b>ActiveState is NOT persisted</b> — the entity has no Active column. On
-///         <see cref="LoadAsync"/> it is restored as <see cref="AlarmActiveState.Inactive"/>;
-///         the engine re-derives it from the live predicate on startup.
-///     </para>
-///     <para>
-///         <b>LastTransitionUtc ↔ UpdatedAtUtc</b>: the table has no dedicated transition
-///         column, so <c>LastTransitionUtc</c> is written into the row-write
-///         <see cref="ScriptedAlarmState.UpdatedAtUtc"/> on save and read back from it on load.
-///     </para>
-///     <para>
-///         <b>LastActiveUtc / LastClearedUtc are transient</b> — they have no columns and
-///         default to <c>null</c> on load (they re-derive from the predicate alongside Active).
-///     </para>
-///     <para>
-///         <see cref="AlarmConditionState.Comments"/> serializes to/from
-///         <see cref="ScriptedAlarmState.CommentsJson"/> via System.Text.Json. An empty list
-///         round-trips as <c>"[]"</c> (matching the entity default).
-///     </para>
-/// </remarks>
-public sealed class EfAlarmConditionStateStore : IAlarmStateStore
-{
-    private static readonly JsonSerializerOptions JsonOptions = new(JsonSerializerDefaults.Web);
-
-    private readonly IDbContextFactory<OtOpcUaConfigDbContext> _dbFactory;
-    private readonly ILogger<EfAlarmConditionStateStore> _logger;
-
-    /// <summary>Initializes a new instance of the <see cref="EfAlarmConditionStateStore"/>.</summary>
-    /// <param name="dbFactory">The factory for creating config database contexts.</param>
-    /// <param name="logger">The logger instance.</param>
-    public EfAlarmConditionStateStore(
-        IDbContextFactory<OtOpcUaConfigDbContext> dbFactory,
-        ILogger<EfAlarmConditionStateStore> logger)
-    {
-        _dbFactory = dbFactory;
-        _logger = logger;
-    }
-
-    /// <inheritdoc />
-    public async Task<AlarmConditionState?> LoadAsync(string alarmId, CancellationToken ct)
-    {
-        using var db = await _dbFactory.CreateDbContextAsync(ct).ConfigureAwait(false);
-        var row = await db.ScriptedAlarmStates.AsNoTracking()
-            .FirstOrDefaultAsync(r => r.ScriptedAlarmId == alarmId, ct)
-            .ConfigureAwait(false);
-        return row is null ? null : MapToState(row);
-    }
-
-    /// <inheritdoc />
-    public async Task<IReadOnlyList<AlarmConditionState>> LoadAllAsync(CancellationToken ct)
-    {
-        using var db = await _dbFactory.CreateDbContextAsync(ct).ConfigureAwait(false);
-        var rows = await db.ScriptedAlarmStates.AsNoTracking()
-            .ToListAsync(ct)
-            .ConfigureAwait(false);
-        return rows.Select(MapToState).ToArray();
-    }
-
-    /// <inheritdoc />
-    public async Task SaveAsync(AlarmConditionState state, CancellationToken ct)
-    {
-        using var db = await _dbFactory.CreateDbContextAsync(ct).ConfigureAwait(false);
-        var row = await db.ScriptedAlarmStates
-            .FirstOrDefaultAsync(r => r.ScriptedAlarmId == state.AlarmId, ct)
-            .ConfigureAwait(false);
-
-        if (row is null)
-        {
-            // Required members are set here to satisfy the compiler; ApplyState is the single
-            // source of truth for all columns and immediately overwrites these values below.
-            row = new ScriptedAlarmState
-            {
-                ScriptedAlarmId = state.AlarmId,
-                EnabledState = MapEnabledToColumn(state.Enabled),
-                AckedState = MapAckedToColumn(state.Acked),
-                ConfirmedState = MapConfirmedToColumn(state.Confirmed),
-                ShelvingState = MapShelvingToColumn(state.Shelving.Kind),
-            };
-            ApplyState(row, state);
-            db.ScriptedAlarmStates.Add(row);
-        }
-        else
-        {
-            ApplyState(row, state);
-        }
-
-        try
-        {
-            await db.SaveChangesAsync(ct).ConfigureAwait(false);
-        }
-        catch (DbUpdateConcurrencyException ex)
-        {
-            // Two writers racing to save the same alarm is benign — last writer wins on
-            // UpdatedAtUtc and the next transition writes again. Log + drop so a race never
-            // crashes the engine.
-            _logger.LogDebug(ex,
-                "EfAlarmConditionStateStore: concurrency conflict for {AlarmId}; dropping save",
-                state.AlarmId);
-        }
-    }
-
-    /// <inheritdoc />
-    public async Task RemoveAsync(string alarmId, CancellationToken ct)
-    {
-        using var db = await _dbFactory.CreateDbContextAsync(ct).ConfigureAwait(false);
-        var row = await db.ScriptedAlarmStates
-            .FirstOrDefaultAsync(r => r.ScriptedAlarmId == alarmId, ct)
-            .ConfigureAwait(false);
-        if (row is null) return;
-
-        db.ScriptedAlarmStates.Remove(row);
-        await db.SaveChangesAsync(ct).ConfigureAwait(false);
-    }
-
-    private static void ApplyState(ScriptedAlarmState row, AlarmConditionState state)
-    {
-        row.EnabledState = MapEnabledToColumn(state.Enabled);
-        row.AckedState = MapAckedToColumn(state.Acked);
-        row.ConfirmedState = MapConfirmedToColumn(state.Confirmed);
-        row.ShelvingState = MapShelvingToColumn(state.Shelving.Kind);
-        row.ShelvingExpiresUtc = state.Shelving.UnshelveAtUtc;
-        row.LastAckUser = state.LastAckUser;
-        row.LastAckComment = state.LastAckComment;
-        row.LastAckUtc = state.LastAckUtc;
-        row.LastConfirmUser = state.LastConfirmUser;
-        row.LastConfirmComment = state.LastConfirmComment;
-        row.LastConfirmUtc = state.LastConfirmUtc;
-        row.CommentsJson = SerializeComments(state.Comments);
-        // No dedicated transition column — persist LastTransitionUtc into UpdatedAtUtc.
-        row.UpdatedAtUtc = state.LastTransitionUtc;
-    }
-
-    private static AlarmConditionState MapToState(ScriptedAlarmState row) => new(
-        AlarmId: row.ScriptedAlarmId,
-        Enabled: string.Equals(row.EnabledState, "Disabled", StringComparison.Ordinal)
-            ? AlarmEnabledState.Disabled
-            : AlarmEnabledState.Enabled,  // unknown string → Enabled (safe default)
-        // Active is not persisted — the engine re-derives it from the predicate at startup.
-        Active: AlarmActiveState.Inactive,
-        Acked: string.Equals(row.AckedState, "Acknowledged", StringComparison.Ordinal)
-            ? AlarmAckedState.Acknowledged
-            : AlarmAckedState.Unacknowledged,  // unknown string → Unacknowledged (safe default)
-        Confirmed: string.Equals(row.ConfirmedState, "Confirmed", StringComparison.Ordinal)
-            ? AlarmConfirmedState.Confirmed
-            : AlarmConfirmedState.Unconfirmed,  // unknown string → Unconfirmed (safe default)
-        Shelving: new ShelvingState(MapShelvingFromColumn(row.ShelvingState), row.ShelvingExpiresUtc),
-        // No transition column — UpdatedAtUtc carries the last transition timestamp.
-        LastTransitionUtc: row.UpdatedAtUtc,
-        // LastActiveUtc / LastClearedUtc have no columns — they re-derive with Active, so null on load.
-        LastActiveUtc: null,
-        LastClearedUtc: null,
-        LastAckUtc: row.LastAckUtc,
-        LastAckUser: row.LastAckUser,
-        LastAckComment: row.LastAckComment,
-        LastConfirmUtc: row.LastConfirmUtc,
-        LastConfirmUser: row.LastConfirmUser,
-        LastConfirmComment: row.LastConfirmComment,
-        Comments: DeserializeComments(row.CommentsJson));
-
-    private static string MapEnabledToColumn(AlarmEnabledState enabled)
-        => enabled == AlarmEnabledState.Enabled ? "Enabled" : "Disabled";
-
-    private static string MapAckedToColumn(AlarmAckedState acked)
-        => acked == AlarmAckedState.Acknowledged ? "Acknowledged" : "Unacknowledged";
-
-    private static string MapConfirmedToColumn(AlarmConfirmedState confirmed)
-        => confirmed == AlarmConfirmedState.Confirmed ? "Confirmed" : "Unconfirmed";
-
-    private static string MapShelvingToColumn(ShelvingKind kind) => kind switch
-    {
-        ShelvingKind.OneShot => "OneShotShelved",
-        ShelvingKind.Timed => "TimedShelved",
-        _ => "Unshelved",
-    };
-
-    private static ShelvingKind MapShelvingFromColumn(string column) => column switch
-    {
-        "OneShotShelved" => ShelvingKind.OneShot,
-        "TimedShelved" => ShelvingKind.Timed,
-        _ => ShelvingKind.Unshelved,  // unknown string → Unshelved (safe default)
-    };
-
-    private static string SerializeComments(ImmutableList<AlarmComment> comments)
-    {
-        if (comments.IsEmpty) return "[]";
-        var dtos = comments.Select(c => new CommentDto
-        {
-            // AlarmComment.TimestampUtc must be DateTimeKind.Utc for correct ISO-8601 round-trip;
-            // the engine always creates AlarmComment instances with Utc kind.
-            TimestampUtc = c.TimestampUtc,
-            User = c.User,
-            Kind = c.Kind,
-            Text = c.Text,
-        });
-        return JsonSerializer.Serialize(dtos, JsonOptions);
-    }
-
-    private static ImmutableList<AlarmComment> DeserializeComments(string? json)
-    {
-        if (string.IsNullOrWhiteSpace(json)) return ImmutableList<AlarmComment>.Empty;
-        var dtos = JsonSerializer.Deserialize<List<CommentDto>>(json, JsonOptions);
-        if (dtos is null || dtos.Count == 0) return ImmutableList<AlarmComment>.Empty;
-        return dtos
-            .Select(d => new AlarmComment(d.TimestampUtc, d.User ?? string.Empty, d.Kind ?? string.Empty, d.Text ?? string.Empty))
-            .ToImmutableList();
-    }
-
-    /// <summary>Stable on-disk shape for a persisted <see cref="AlarmComment"/> in <c>CommentsJson</c>.</summary>
-    private sealed class CommentDto
-    {
-        /// <summary>When the comment was recorded (UTC).</summary>
-        public DateTime TimestampUtc { get; set; }
-
-        /// <summary>Identity of the actor that wrote the comment.</summary>
-        public string? User { get; set; }
-
-        /// <summary>Human-readable classification of the comment (Acknowledge, Confirm, …).</summary>
-        public string? Kind { get; set; }
-
-        /// <summary>Operator-supplied or engine-generated comment text.</summary>
-        public string? Text { get; set; }
-    }
-}

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

@@ -286,8 +286,7 @@ public static class ServiceCollectionExtensions
             // Per-cluster mesh Phase 4: scripted-alarm condition-state store. Registered by the Host's
             // AddOtOpcUaLocalDb on driver-role nodes (the replicated LocalDb store), so condition state
             // persists with no ConfigDb; null elsewhere (admin-only graphs, test harnesses) → the actor
-            // falls back to an EfAlarmConditionStateStore over dbFactory, or skips the alarm host when
-            // there is no ConfigDb either.
+            // skips spawning the alarm host (the ConfigDb-backed EF fallback was retired in Phase 4 Task 9).
             var alarmStateStore = resolver.GetService<IAlarmStateStore>();
             // Per-cluster mesh Phase 3: ConfigSource:Mode selects where this driver reads config.
             // FetchAndCache pulls the artifact from central over gRPC and reads only the LocalDb cache;
@@ -473,7 +472,8 @@ public static class ServiceCollectionExtensions
                 // gated on hasAdmin and driver-only nodes are forced to FetchAndCache. DriverHostActor
                 // guards every ConfigDb-touching path on it (UpsertNodeDeploymentState no-ops; central
                 // persists acks from the ApplyAck) and serves scripted-alarm state from the LocalDb
-                // alarmStateStore instead of an EfAlarmConditionStateStore.
+                // alarmStateStore (there is no ConfigDb-backed EF fallback; the host skips the alarm
+                // host when no store was wired).
                 DriverHostActor.Props(dbFactory, roleInfo.LocalNode,
                     ackRouter: useClusterClient ? nodeComm : null,
                     driverFactory: driverFactory, localRoles: roleInfo.LocalRoles,

tests/Core/ZB.MOM.WW.OtOpcUa.Configuration.Tests/SchemaComplianceTests.cs

@@ -36,8 +36,10 @@ public sealed class SchemaComplianceTests
             "DriverHostStatus",
             "DriverInstanceResilienceStatus",
             "LdapGroupRoleMapping",
-            // v3 dropped the orphaned EquipmentImportBatch / EquipmentImportRow tables
-            "Script", "ScriptedAlarm", "ScriptedAlarmState",
+            // v3 dropped the orphaned EquipmentImportBatch / EquipmentImportRow tables.
+            // ScriptedAlarmState was dropped in per-cluster mesh Phase 4 (Task 9) — scripted-alarm
+            // condition state moved to the replicated LocalDb store.
+            "Script", "ScriptedAlarm",
             // v2 deploy-model tables (Phase 1 of Akka + fused-hosting alignment)
             "Deployment", "NodeDeploymentState", "ConfigEdit", "DataProtectionKeys",
         };

tests/Core/ZB.MOM.WW.OtOpcUa.Configuration.Tests/ScriptingEntitiesTests.cs

@@ -10,9 +10,9 @@ namespace ZB.MOM.WW.OtOpcUa.Configuration.Tests;
 
 /// <summary>
 ///     Verifies the Phase 7 Stream E entities (<see cref="Script"/>, <see cref="VirtualTag"/>,
-///     <see cref="ScriptedAlarm"/>, <see cref="ScriptedAlarmState"/>) register correctly in
-///     the EF model, map to the expected tables/columns/indexes, and carry the check constraints
-///     the plan decisions call for. Introspection only — no SQL Server required.
+///     <see cref="ScriptedAlarm"/>) register correctly in the EF model, map to the expected
+///     tables/columns/indexes, and carry the check constraints the plan decisions call for.
+///     Introspection only — no SQL Server required.
 /// </summary>
 [Trait("Category", "Unit")]
 public sealed class ScriptingEntitiesTests
@@ -127,49 +127,9 @@ public sealed class ScriptingEntitiesTests
         alarm.Enabled.ShouldBeTrue();
     }
 
-    /// <summary>Verifies that ScriptedAlarmState is keyed on ScriptedAlarmId and not generation-scoped.</summary>
-    [Fact]
-    public void ScriptedAlarmState_keyed_on_ScriptedAlarmId_not_generation_scoped()
-    {
-        using var ctx = BuildCtx();
-        var entity = ctx.Model.FindEntityType(typeof(ScriptedAlarmState)).ShouldNotBeNull();
-        entity.GetTableName().ShouldBe("ScriptedAlarmState");
-
-        var pk = entity.FindPrimaryKey().ShouldNotBeNull();
-        pk.Properties.Count.ShouldBe(1);
-        pk.Properties[0].Name.ShouldBe(nameof(ScriptedAlarmState.ScriptedAlarmId));
-
-        // State is NOT generation-scoped — GenerationId column should not exist per plan decision #14.
-        entity.FindProperty("GenerationId").ShouldBeNull(
-            "ack state follows alarm identity across generations");
-    }
-
-    /// <summary>Verifies that ScriptedAlarmState default values match Part 9 initial states.</summary>
-    [Fact]
-    public void ScriptedAlarmState_default_state_values_match_Part9_initial_states()
-    {
-        var state = new ScriptedAlarmState
-        {
-            ScriptedAlarmId = "a1",
-            EnabledState = "Enabled",
-            AckedState = "Unacknowledged",
-            ConfirmedState = "Unconfirmed",
-            ShelvingState = "Unshelved",
-        };
-        state.CommentsJson.ShouldBe("[]");
-        state.LastAckUser.ShouldBeNull();
-        state.LastAckUtc.ShouldBeNull();
-    }
-
-    /// <summary>Verifies that ScriptedAlarmState has a JSON check constraint on CommentsJson.</summary>
-    [Fact]
-    public void ScriptedAlarmState_has_JSON_check_constraint_on_CommentsJson()
-    {
-        using var ctx = BuildCtx();
-        var entity = DesignModel(ctx).FindEntityType(typeof(ScriptedAlarmState)).ShouldNotBeNull();
-        var checks = entity.GetCheckConstraints().Select(c => c.Name).ToArray();
-        checks.ShouldContain("CK_ScriptedAlarmState_CommentsJson_IsJson");
-    }
+    // The ConfigDb-backed ScriptedAlarmState entity + table were retired in per-cluster mesh Phase 4
+    // (Task 9): scripted-alarm condition state lives in the replicated LocalDb store. The entity-model
+    // tests that covered it are gone with it.
 
     /// <summary>Verifies that all new Phase 7 entities are exposed via DbSet properties.</summary>
     [Fact]
@@ -179,7 +139,6 @@ public sealed class ScriptingEntitiesTests
         ctx.Scripts.ShouldNotBeNull();
         ctx.VirtualTags.ShouldNotBeNull();
         ctx.ScriptedAlarms.ShouldNotBeNull();
-        ctx.ScriptedAlarmStates.ShouldNotBeNull();
     }
 
     /// <summary>Verifies that the squashed V3Initial migration exists in the assembly.</summary>

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverHostActorDbLessTests.cs

@@ -177,11 +177,13 @@ public sealed class DriverHostActorDbLessTests : RuntimeActorTestBase
     }
 
     /// <summary>
-    ///     Regression — a DB-backed actor (non-null <c>dbFactory</c>, no alarm store passed) still spawns
-    ///     the host on the EF-store fallback path, exactly as before Phase 4.
+    ///     Phase 4 Task 9 — the ConfigDb-backed EF fallback is retired. A DB-backed actor (non-null
+    ///     <c>dbFactory</c>) with no alarm store now SKIPS the ScriptedAlarm host: the wired
+    ///     <c>IAlarmStateStore</c> is the only source of condition-state persistence, and there is no
+    ///     longer an EF store constructed over <c>dbFactory</c>.
     /// </summary>
     [Fact]
-    public void DbBackedNode_WithNoStore_StillSpawnsScriptedAlarmHost_OnEfFallback()
+    public void DbBackedNode_WithNoStore_SkipsScriptedAlarmHost()
     {
         var publish = CreateTestProbe();
         var actor = Sys.ActorOf(DriverHostActor.Props(
@@ -192,7 +194,7 @@ public sealed class DriverHostActorDbLessTests : RuntimeActorTestBase
             alarmStateStore: null));
 
         AwaitStarted(actor);
-        ResolveChild(actor, "scripted-alarm-host").ShouldNotBeNull();
+        ResolveChild(actor, "scripted-alarm-host").ShouldBeNull();
     }
 
     /// <summary>

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ScriptedAlarms/EfAlarmConditionStateStoreTests.cs

@@ -1,244 +0,0 @@
-using System.Collections.Immutable;
-using Microsoft.Extensions.Logging.Abstractions;
-using Shouldly;
-using Xunit;
-using ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms;
-using ZB.MOM.WW.OtOpcUa.Runtime.ScriptedAlarms;
-using ZB.MOM.WW.OtOpcUa.Runtime.Tests.Harness;
-
-namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.ScriptedAlarms;
-
-/// <summary>
-///     Round-trip + upsert + lifecycle coverage for <see cref="EfAlarmConditionStateStore"/>,
-///     the EF-backed <see cref="IAlarmStateStore"/> over the <c>ScriptedAlarmState</c> table.
-/// </summary>
-public sealed class EfAlarmConditionStateStoreTests : RuntimeActorTestBase
-{
-    private static EfAlarmConditionStateStore NewStore(out Microsoft.EntityFrameworkCore.IDbContextFactory<ZB.MOM.WW.OtOpcUa.Configuration.OtOpcUaConfigDbContext> db)
-    {
-        db = NewInMemoryDbFactory();
-        return new EfAlarmConditionStateStore(db, NullLogger<EfAlarmConditionStateStore>.Instance);
-    }
-
-    private static AlarmConditionState Sample(
-        string alarmId,
-        AlarmActiveState active = AlarmActiveState.Inactive,
-        ShelvingState? shelving = null,
-        ImmutableList<AlarmComment>? comments = null)
-    {
-        var t = new DateTime(2026, 06, 10, 12, 00, 00, DateTimeKind.Utc);
-        return new AlarmConditionState(
-            AlarmId: alarmId,
-            Enabled: AlarmEnabledState.Disabled,
-            Active: active,
-            Acked: AlarmAckedState.Unacknowledged,
-            Confirmed: AlarmConfirmedState.Unconfirmed,
-            Shelving: shelving ?? new ShelvingState(ShelvingKind.Timed, t.AddMinutes(30)),
-            LastTransitionUtc: t,
-            LastActiveUtc: t.AddMinutes(-5),
-            LastClearedUtc: t.AddMinutes(-1),
-            LastAckUtc: t.AddMinutes(-2),
-            LastAckUser: "jane",
-            LastAckComment: "ack-comment",
-            LastConfirmUtc: t.AddMinutes(-3),
-            LastConfirmUser: "bob",
-            LastConfirmComment: "confirm-comment",
-            Comments: comments ?? ImmutableList<AlarmComment>.Empty);
-    }
-
-    /// <summary>Save then load round-trips every persisted operator-state + audit field.</summary>
-    [Fact]
-    public async Task SaveAsync_then_LoadAsync_round_trips_persisted_fields()
-    {
-        var store = NewStore(out _);
-        var state = Sample("alarm-1");
-
-        await store.SaveAsync(state, CancellationToken.None);
-        var loaded = await store.LoadAsync("alarm-1", CancellationToken.None);
-
-        loaded.ShouldNotBeNull();
-        loaded.AlarmId.ShouldBe("alarm-1");
-        loaded.Enabled.ShouldBe(AlarmEnabledState.Disabled);
-        loaded.Acked.ShouldBe(AlarmAckedState.Unacknowledged);
-        loaded.Confirmed.ShouldBe(AlarmConfirmedState.Unconfirmed);
-        loaded.Shelving.Kind.ShouldBe(ShelvingKind.Timed);
-        loaded.Shelving.UnshelveAtUtc.ShouldBe(state.Shelving.UnshelveAtUtc);
-        loaded.LastTransitionUtc.ShouldBe(state.LastTransitionUtc);
-        loaded.LastAckUtc.ShouldBe(state.LastAckUtc);
-        loaded.LastAckUser.ShouldBe("jane");
-        loaded.LastAckComment.ShouldBe("ack-comment");
-        loaded.LastConfirmUtc.ShouldBe(state.LastConfirmUtc);
-        loaded.LastConfirmUser.ShouldBe("bob");
-        loaded.LastConfirmComment.ShouldBe("confirm-comment");
-    }
-
-    /// <summary>Loading an id that was never saved returns null.</summary>
-    [Fact]
-    public async Task LoadAsync_for_unknown_id_returns_null()
-    {
-        var store = NewStore(out _);
-
-        var loaded = await store.LoadAsync("never-saved", CancellationToken.None);
-
-        loaded.ShouldBeNull();
-    }
-
-    /// <summary>Active is not persisted — a saved Active state loads back as Inactive.</summary>
-    [Fact]
-    public async Task Active_is_ignored_on_load_and_defaults_to_Inactive()
-    {
-        var store = NewStore(out _);
-        await store.SaveAsync(Sample("alarm-active", active: AlarmActiveState.Active), CancellationToken.None);
-
-        var loaded = await store.LoadAsync("alarm-active", CancellationToken.None);
-
-        loaded.ShouldNotBeNull();
-        loaded.Active.ShouldBe(AlarmActiveState.Inactive);
-    }
-
-    /// <summary>LastActiveUtc / LastClearedUtc have no columns and default to null on load.</summary>
-    [Fact]
-    public async Task Derived_timestamps_default_to_null_on_load()
-    {
-        var store = NewStore(out _);
-        await store.SaveAsync(Sample("alarm-derived"), CancellationToken.None);
-
-        var loaded = await store.LoadAsync("alarm-derived", CancellationToken.None);
-
-        loaded.ShouldNotBeNull();
-        loaded.LastActiveUtc.ShouldBeNull();
-        loaded.LastClearedUtc.ShouldBeNull();
-    }
-
-    /// <summary>Unshelved round-trips with a null UnshelveAtUtc.</summary>
-    [Fact]
-    public async Task Unshelved_round_trips()
-    {
-        var store = NewStore(out _);
-        await store.SaveAsync(
-            Sample("alarm-unshelved", shelving: ShelvingState.Unshelved),
-            CancellationToken.None);
-
-        var loaded = await store.LoadAsync("alarm-unshelved", CancellationToken.None);
-
-        loaded.ShouldNotBeNull();
-        loaded.Shelving.Kind.ShouldBe(ShelvingKind.Unshelved);
-        loaded.Shelving.UnshelveAtUtc.ShouldBeNull();
-    }
-
-    /// <summary>OneShot shelving round-trips.</summary>
-    [Fact]
-    public async Task OneShot_shelving_round_trips()
-    {
-        var store = NewStore(out _);
-        await store.SaveAsync(
-            Sample("alarm-oneshot", shelving: new ShelvingState(ShelvingKind.OneShot, null)),
-            CancellationToken.None);
-
-        var loaded = await store.LoadAsync("alarm-oneshot", CancellationToken.None);
-
-        loaded.ShouldNotBeNull();
-        loaded.Shelving.Kind.ShouldBe(ShelvingKind.OneShot);
-        loaded.Shelving.UnshelveAtUtc.ShouldBeNull();
-    }
-
-    /// <summary>The append-only comment trail round-trips all four fields per comment.</summary>
-    [Fact]
-    public async Task Comments_round_trip_all_fields()
-    {
-        var store = NewStore(out _);
-        var c1 = new AlarmComment(
-            new DateTime(2026, 06, 10, 10, 00, 00, DateTimeKind.Utc), "jane", "Acknowledge", "checking pump");
-        var c2 = new AlarmComment(
-            new DateTime(2026, 06, 10, 11, 30, 00, DateTimeKind.Utc), "bob", "Confirm", "all clear");
-        var comments = ImmutableList.Create(c1, c2);
-
-        await store.SaveAsync(Sample("alarm-comments", comments: comments), CancellationToken.None);
-        var loaded = await store.LoadAsync("alarm-comments", CancellationToken.None);
-
-        loaded.ShouldNotBeNull();
-        loaded.Comments.Count.ShouldBe(2);
-        loaded.Comments[0].TimestampUtc.ShouldBe(c1.TimestampUtc);
-        loaded.Comments[0].User.ShouldBe("jane");
-        loaded.Comments[0].Kind.ShouldBe("Acknowledge");
-        loaded.Comments[0].Text.ShouldBe("checking pump");
-        loaded.Comments[1].TimestampUtc.ShouldBe(c2.TimestampUtc);
-        loaded.Comments[1].User.ShouldBe("bob");
-        loaded.Comments[1].Kind.ShouldBe("Confirm");
-        loaded.Comments[1].Text.ShouldBe("all clear");
-    }
-
-    /// <summary>An empty comment list round-trips as an empty list.</summary>
-    [Fact]
-    public async Task Empty_comments_round_trip()
-    {
-        var store = NewStore(out _);
-        await store.SaveAsync(
-            Sample("alarm-empty-comments", comments: ImmutableList<AlarmComment>.Empty),
-            CancellationToken.None);
-
-        var loaded = await store.LoadAsync("alarm-empty-comments", CancellationToken.None);
-
-        loaded.ShouldNotBeNull();
-        loaded.Comments.ShouldBeEmpty();
-    }
-
-    /// <summary>Saving the same id twice is an upsert — one row, latest values win.</summary>
-    [Fact]
-    public async Task SaveAsync_twice_upserts_latest()
-    {
-        var store = NewStore(out var db);
-        var first = Sample("alarm-upsert") with { LastAckUser = "first-user", Enabled = AlarmEnabledState.Enabled };
-        var second = Sample("alarm-upsert") with { LastAckUser = "second-user", Enabled = AlarmEnabledState.Disabled };
-
-        await store.SaveAsync(first, CancellationToken.None);
-        await store.SaveAsync(second, CancellationToken.None);
-
-        using (var ctx = db.CreateDbContext())
-        {
-            ctx.ScriptedAlarmStates.Count(r => r.ScriptedAlarmId == "alarm-upsert").ShouldBe(1);
-        }
-
-        var loaded = await store.LoadAsync("alarm-upsert", CancellationToken.None);
-        loaded.ShouldNotBeNull();
-        loaded.LastAckUser.ShouldBe("second-user");
-        loaded.Enabled.ShouldBe(AlarmEnabledState.Disabled);
-    }
-
-    /// <summary>LoadAllAsync returns every saved state.</summary>
-    [Fact]
-    public async Task LoadAllAsync_returns_all_saved_states()
-    {
-        var store = NewStore(out _);
-        await store.SaveAsync(Sample("a-1"), CancellationToken.None);
-        await store.SaveAsync(Sample("a-2"), CancellationToken.None);
-        await store.SaveAsync(Sample("a-3"), CancellationToken.None);
-
-        var all = await store.LoadAllAsync(CancellationToken.None);
-
-        all.Select(s => s.AlarmId).OrderBy(x => x).ShouldBe(new[] { "a-1", "a-2", "a-3" });
-    }
-
-    /// <summary>RemoveAsync deletes a row so a subsequent load returns null; others survive.</summary>
-    [Fact]
-    public async Task RemoveAsync_deletes_one_and_LoadAsync_returns_null()
-    {
-        var store = NewStore(out _);
-        await store.SaveAsync(Sample("keep"), CancellationToken.None);
-        await store.SaveAsync(Sample("drop"), CancellationToken.None);
-
-        await store.RemoveAsync("drop", CancellationToken.None);
-
-        (await store.LoadAsync("drop", CancellationToken.None)).ShouldBeNull();
-        (await store.LoadAsync("keep", CancellationToken.None)).ShouldNotBeNull();
-    }
-
-    /// <summary>Removing an unknown id is a no-op (does not throw).</summary>
-    [Fact]
-    public async Task RemoveAsync_for_unknown_id_is_noop()
-    {
-        var store = NewStore(out _);
-
-        await Should.NotThrowAsync(() => store.RemoveAsync("ghost", CancellationToken.None));
-    }
-}