merge(agent-c): row 100 — SiteScriptCompileCache becomes an instance-scoped sealed class owned by the ScriptCompilationService DI singleton (zero production Clear() callers existed, so Clear() is deleted outright); row-91 serialized collection relaxed and delta assertions restored to exact counts; new registration test pins the load-bearing singleton lifetime

src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/DeploymentManagerActor.cs

@@ -677,7 +677,8 @@ public class DeploymentManagerActor : ReceiveActor, IWithTimers
                 {
                     // Verdict discarded: startup does not gate on compile failures (a failing
                     // script is logged by the Instance Actor and leaves the rest running).
-                    // This call exists only to populate SiteScriptCompileCache.
+                    // This call exists only to populate the compile cache owned by the
+                    // shared ScriptCompilationService (SiteScriptCompileCache).
                     validator.Validate(configJson);
                 }
                 catch
@@ -798,8 +799,8 @@ public class DeploymentManagerActor : ReceiveActor, IWithTimers
     }
 
     /// <summary>
-    /// Compiles the deployment's scripts off the actor thread purely to populate the
-    /// process-wide <see cref="SiteScriptCompileCache"/>, then pipes
+    /// Compiles the deployment's scripts off the actor thread purely to populate the compile
+    /// cache owned by the shared <c>ScriptCompilationService</c> singleton, then pipes
     /// <see cref="DeployCompileWarmed"/> back so the authoritative gate can run on the actor
     /// thread against a warm cache. The warm is best-effort: its verdict is discarded and any
     /// exception swallowed, because <see cref="RunDeployGateAndProceed"/> re-derives the
@@ -910,9 +911,10 @@ public class DeploymentManagerActor : ReceiveActor, IWithTimers
         // already been warmed off-thread (StartDeployCompileWarm), so this call is
         // pure cache hits and no longer holds the singleton — while the per-instance
         // warm guard keeps this instance's own command ordering intact. Redeploys and
-        // multi-instance deploys of unchanged scripts hit the process-wide compile
-        // cache (SiteScriptCompileCache) too, and the Instance Actor's PreStart reuses
-        // the gate's compile (N4).
+        // multi-instance deploys of unchanged scripts hit the compile cache
+        // (SiteScriptCompileCache, owned by the ScriptCompilationService singleton this
+        // actor shares with every Instance Actor) too, and the Instance Actor's PreStart
+        // reuses the gate's compile (N4).
         var errors = _deployCompileValidator.Validate(command.FlattenedConfigurationJson);
         if (errors.Count > 0)
         {