perf(sitelog): sampled per-run events; interval run summaries; site_events replication policy pinned

Implements WP3.2 stage (b) per docs/plans/2026-08-15-site-events-policy-design.md.

- Per-run instance-script Started/Completed Info site events are now off by
  default (SiteRuntimeOptions.PerRunScriptEvents=false) instead of firing on
  every run, closing the dominant site_events writer. Gated at the ScriptRunLauncher
  call sites (moved there from ScriptExecutionActor by WP3.1). Error-level events
  (timeout/failure/stuck-watchdog/recursion-limit) remain unconditional.
- ScriptRunSummaryRecorder accumulates per-(instance, script) run counters and a
  new site-only ScriptRunSummaryFlushService emits one aggregate "script" Info
  site event per ScriptRunSummaryIntervalSeconds (default 300s), top-50-script
  breakdown with an "others" rollup, zero-activity intervals emit nothing.
- Per-script opt-in via PerRunScriptEventScripts ("Instance/Script" exact or
  "Instance/*" wildcard), matched by the new pure ScriptRunEventPolicy. All three
  options are read from IOptionsMonitor<SiteRuntimeOptions> per run, so the
  policy is hot-togglable without a restart.
- Fixed the stale "event log is not replicated" comment at AkkaHostedService.cs
  (~905): site_events IS registered in SiteLocalDbSetup.ReplicatedTables — the
  singleton is what makes queries always hit the actively-written copy;
  replication is what gives the singleton history to read after a failover
  (memo Decision (b)). site_events replication itself is unchanged (still
  registered) and already pinned by
  tests/ZB.MOM.WW.ScadaBridge.Host.Tests/SiteLocalDbCdcRegistrationTests.cs.
- Updated Component-SiteEventLogging.md (Volume Policy section, corrected
  Storage/replication rationale) and Component-SiteRuntime.md (Script Run
  Launch + Error Handling sections).

tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/TestSupport/FakeSiteEventLogger.cs

@@ -1,6 +1,8 @@
 using System.Collections.Concurrent;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
 using ZB.MOM.WW.ScadaBridge.SiteEventLogging;
+using ZB.MOM.WW.ScadaBridge.SiteRuntime.Scripts;
 
 namespace ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests.TestSupport;
 
@@ -59,16 +61,34 @@ public sealed class FakeSiteEventLogger : ISiteEventLogger
 /// don't throw before they reach the logging hot path.
 /// </para>
 /// </summary>
-public sealed class SingleServiceProvider(ISiteEventLogger logger)
+/// <param name="logger">The event logger to resolve for <see cref="ISiteEventLogger"/>.</param>
+/// <param name="optionsMonitor">
+/// WP3.2: optional <see cref="IOptionsMonitor{TOptions}"/> for <see cref="SiteRuntimeOptions"/>
+/// — resolves for the hot-toggle tests; null (the default) exercises the launcher's
+/// constructor-passed-options fallback, matching every pre-WP3.2 caller of this class.
+/// </param>
+/// <param name="summaryRecorder">
+/// WP3.2: optional <see cref="ScriptRunSummaryRecorder"/> — resolves so a test can assert on
+/// the aggregate counters a run produced; null (the default) exercises the launcher's
+/// null-safe skip path.
+/// </param>
+public sealed class SingleServiceProvider(
+    ISiteEventLogger logger,
+    IOptionsMonitor<SiteRuntimeOptions>? optionsMonitor = null,
+    ScriptRunSummaryRecorder? summaryRecorder = null)
     : IServiceProvider, IServiceScopeFactory, IServiceScope
 {
     private readonly ISiteEventLogger _logger = logger;
+    private readonly IOptionsMonitor<SiteRuntimeOptions>? _optionsMonitor = optionsMonitor;
+    private readonly ScriptRunSummaryRecorder? _summaryRecorder = summaryRecorder;
 
     /// <inheritdoc />
     public object? GetService(Type serviceType)
     {
         if (serviceType == typeof(ISiteEventLogger)) return _logger;
         if (serviceType == typeof(IServiceScopeFactory)) return this;
+        if (serviceType == typeof(IOptionsMonitor<SiteRuntimeOptions>)) return _optionsMonitor;
+        if (serviceType == typeof(ScriptRunSummaryRecorder)) return _summaryRecorder;
         return null;
     }