test(siteruntime): gate ReconcileStartsInstanceTests on the DM's first instance-count report (register row 83)

Row 67's suite still opened every test with a bare Task.Delay(500) after
constructing the Deployment Manager. Each test then writes its
deployed_configurations row -- and a row that lands before the boot-time load
reads storage is picked up by that load, which means the test passes while
proving the BOOT LOAD works rather than the startup-reconcile path it names. A
sleep only makes that race unlikely; on a loaded machine the load can still be
in flight when it expires and the test silently changes what it proves instead
of failing.

The row-78 fix session hit exactly this trap and closed it in
InstanceSweepSelfHealTests by gating on the first
ISiteHealthCollector.SetInstanceCounts report -- the edge the manager raises
unconditionally the moment its load completes, including for an empty site.
This applies the same gate here.

The probe is now a shared TestSupport helper (DeploymentManagerStartupProbe,
added with row 85) rather than a private nested class, so both suites use one
implementation.

Also pins InstanceSweepIntervalSeconds = 0 for this suite: with the sweep armed
its periodic self-heal would independently start the same instances and the
suite would stop distinguishing the row-67 mechanism from the row-78 one.

The remaining Task.Delay calls in the file are deliberate and left alone -- they
precede assertions that NOTHING happened (a disabled instance stayed stopped, a
redundant ensure-started changed nothing), which cannot be awaited on. The one
delay that was a readiness wait rather than an absence wait is now an
AwaitAssertAsync on the instance actually being routable.

tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/ReconcileStartsInstanceTests.cs

@@ -68,20 +68,49 @@ public class ReconcileStartsInstanceTests : TestKit, IDisposable
         TestLocalDb.DeleteFiles(path);
     }
 
-    private IActorRef CreateDeploymentManager(IServiceProvider? serviceProvider = null) =>
-        ActorOf(Props.Create(() => new DeploymentManagerActor(
+    /// <summary>
+    /// Starts a Deployment Manager and blocks until its boot-time config load has PROVABLY read
+    /// storage — its first <c>ISiteHealthCollector.SetInstanceCounts</c> report.
+    ///
+    /// <para>
+    /// <b>Deferred register row 83.</b> This used to be a bare <c>Task.Delay(500)</c>. Every test
+    /// here writes its <c>deployed_configurations</c> row AFTER the manager is constructed, and a
+    /// row that lands before the boot load reads storage is picked up by that load — so the test
+    /// would still pass, while proving the BOOT LOAD works rather than the startup-reconcile path
+    /// it claims to cover. A sleep only makes that race unlikely; on a loaded machine the load can
+    /// still be in flight when it expires, and the test silently changes what it proves instead of
+    /// failing. The row-78 fix session hit exactly this trap and closed it in
+    /// <c>InstanceSweepSelfHealTests</c>; this is the same gate, applied to row 67's suite.
+    /// </para>
+    ///
+    /// <para>
+    /// The sweep is disabled (<c>InstanceSweepIntervalSeconds = 0</c>) so these tests keep proving
+    /// the row-67 <see cref="EnsureInstanceStartedCommand"/> path specifically — with the sweep
+    /// armed, its periodic self-heal would independently start the same instances and the suite
+    /// would no longer distinguish the two mechanisms.
+    /// </para>
+    /// </summary>
+    private IActorRef CreateDeploymentManager(IServiceProvider? serviceProvider = null)
+    {
+        var health = new DeploymentManagerStartupProbe();
+        var dm = ActorOf(Props.Create(() => new DeploymentManagerActor(
             _storage,
             _compilationService,
             _sharedScriptLibrary,
             null,
-            new SiteRuntimeOptions(),
+            new SiteRuntimeOptions { InstanceSweepIntervalSeconds = 0 },
             NullLogger<DeploymentManagerActor>.Instance,
             dclManager: null,
-            healthCollector: null,
+            healthCollector: health,
             serviceProvider: serviceProvider,
             loggerFactory: null,
             configFetcher: null)));
 
+        AwaitCondition(() => health.ReportCount > 0, TimeSpan.FromSeconds(20),
+            TimeSpan.FromMilliseconds(25));
+        return dm;
+    }
+
     private IActorRef CreateReconciliationActor(
         IActorRef siteCommunicationActor,
         IDeploymentConfigFetcher fetcher,
@@ -143,7 +172,6 @@ public class ReconcileStartsInstanceTests : TestKit, IDisposable
         // Boot the Deployment Manager against EMPTY storage — this is the missing-config boot
         // (lost volume / first boot after a restore / rehomed data dir).
         var dm = CreateDeploymentManager();
-        await Task.Delay(500);
 
         // Baseline: the instance is genuinely not running.
         Assert.False(await InstanceIsRunningAsync(dm, "HealedPump"));
@@ -188,7 +216,6 @@ public class ReconcileStartsInstanceTests : TestKit, IDisposable
     {
         var siteLog = new FakeSiteEventLogger();
         var dm = CreateDeploymentManager(new SingleServiceProvider(siteLog));
-        await Task.Delay(500);
 
         const string instanceName = "SurfacedPump";
         await _storage.StoreDeployedConfigAsync(
@@ -286,18 +313,21 @@ public class ReconcileStartsInstanceTests : TestKit, IDisposable
     public async Task EnsureInstanceStarted_IsIdempotent_WhenAlreadyRunning()
     {
         var dm = CreateDeploymentManager();
-        await Task.Delay(500);
 
         const string instanceName = "IdempotentPump";
         dm.Tell(new DeployInstanceCommand(
             "dep-idem", instanceName, "sha256:abc",
             MakeConfigJson(instanceName), "admin", DateTimeOffset.UtcNow));
         ExpectMsg<DeploymentStatusResponse>(TimeSpan.FromSeconds(5));
-        await Task.Delay(1000);
+
+        // Wait on the instance actually being routable, not on the clock.
+        await AwaitAssertAsync(async () =>
+            Assert.True(await InstanceIsRunningAsync(dm, instanceName)), TimeSpan.FromSeconds(10));
 
         var before = await ResolveInstanceChildAsync(dm, instanceName);
 
-        // Two redundant ensure-started requests, as the two nodes would send.
+        // Two redundant ensure-started requests, as the two nodes would send. This one IS a
+        // settle wait: the assertion below is that nothing happened, which cannot be awaited on.
         dm.Tell(new EnsureInstanceStartedCommand(instanceName, "startup reconcile"));
         dm.Tell(new EnsureInstanceStartedCommand(instanceName, "startup reconcile"));
         await Task.Delay(1000);
@@ -317,7 +347,6 @@ public class ReconcileStartsInstanceTests : TestKit, IDisposable
     public async Task EnsureInstanceStarted_DisabledInstance_StaysStopped()
     {
         var dm = CreateDeploymentManager();
-        await Task.Delay(500);
 
         const string instanceName = "DisabledPump";
         await _storage.StoreDeployedConfigAsync(
@@ -338,7 +367,6 @@ public class ReconcileStartsInstanceTests : TestKit, IDisposable
     public async Task EnsureInstanceStarted_UnknownInstance_IsAQuietNoOp()
     {
         var dm = CreateDeploymentManager();
-        await Task.Delay(500);
 
         dm.Tell(new EnsureInstanceStartedCommand("NeverHeardOf", "startup reconcile"));
         await Task.Delay(1500);