fix(runtime): malformed artifact bytes on boot/restore are no answer (#601); evict telemetry snapshots on driver removal (#609)

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

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

@@ -80,6 +80,32 @@ public sealed class DriverHostActorBootFromCacheTests : RuntimeActorTestBase
         rebuild.Artifact.ShouldBe(blob);
     }
 
+    [Theory]
+    [InlineData("not json at all")]
+    [InlineData("{\"DriverInstances\": [")]               // truncated JSON
+    [InlineData("\u001f\u008b\u0008garbage-after-gzip-magic")] // gzip magic, undecompressible body
+    public void BootFromCache_withMalformedNonEmptyBytes_isNoAnswer_notAnEmptyConfiguration(string text)
+    {
+        // #601 (S-10): the lenient parse turned malformed bytes into "zero driver specs", which plans every
+        // running child for StopChild and then rebuilds the address space from the garbage. Malformed bytes
+        // must be treated like the zero-length case: nothing reconciled, nothing rebuilt.
+        var cached = new CachedDeploymentArtifact(
+            DeploymentId.NewId().ToString(), CachedRev.Value,
+            System.Text.Encoding.Latin1.GetBytes(text), DateTimeOffset.UtcNow.AddHours(-1));
+        var publishProbe = CreateTestProbe();
+
+        var actor = Sys.ActorOf(DriverHostActor.Props(
+            new ThrowingDbFactory(), TestNode, ackRouter: null,
+            localRoles: new HashSet<string> { "driver" },
+            opcUaPublishActor: publishProbe.Ref,
+            deploymentArtifactCache: new StubArtifactCache(cached)));
+
+        // Barrier: diagnostics are served only after PreStart's boot work ran, so the absence below is
+        // asserted after the boot path had its chance to Tell (positive control is the valid-bytes test).
+        AskDiagnostics(actor);
+        publishProbe.ExpectNoMsg(TimeSpan.FromMilliseconds(500));
+    }
+
     [Fact]
     public void CentralUnreachableAndCacheEmpty_StaysStaleWithNoConfiguration()
     {