fix(api-surface): close Theme 9 — 27 naming / dead-code / config / hygiene findings

The largest themed batch — small mechanical fixes across 11 modules.

API / message hygiene:
- Comm-020: SiteAddressCacheLoaded now carries IReadOnlyDictionary /
  IReadOnlyList — Akka messages must be immutable.
- Commons-016: BundleSession.MaxUnlockAttempts named constant replaces
  magic 3.
- Commons-018: IOperationTrackingStore + IPartitionMaintenance moved from
  Interfaces/ root to Interfaces/Services/ (namespace preserved — 9
  consumers exceeded the in-prompt move threshold).
- Commons-023: TrackingStatusSnapshot.SourceNode now consistent with the
  trailing-optional-with-default pattern used elsewhere.
- SR-022: AuditingDbCommand.DbConnection.set no longer uses reflection —
  exposes AuditingDbConnection.Inner via internal API surface.

Dead code / config cleanup:
- ClusterInfra-011: decorative SectionName constant deleted.
- ClusterInfra-014: dead AddClusterInfrastructureActors method + its
  "throws-when-called" test deleted.
- Host-021: Microsoft Logging:LogLevel block deleted from appsettings.json
  (dead under Serilog).

Fail-loud over fail-silent:
- DM-021: ResolveSiteIdentifierAsync throws on missing site (was silently
  substituting a DB id).
- DM-022: dropped transient Pending write — record now lands directly in
  InProgress (no UI flicker, one fewer DB write).
- Host-020: LoggerConfigurationFactory emits a Console.Error warning when
  both Serilog:MinimumLevel and ScadaLink:Logging:MinimumLevel are set
  (ScadaLink remains truth per Host-011).
- SnF-022: NotifyCachedCallObserverAsync logs Warning on unparseable
  TrackedOperationId (was silently dropping).
- SnF-023: empty siteId default replaced with $unknown-site sentinel
  + constructor normalisation.

Correctness:
- SCA-001: SupervisorStrategy XML rewritten to match actual
  DefaultDecider/Restart semantics (was claiming Resume).
- SCA-003: OnUpsertAsync now restamps IngestedAtUtc on every upsert.
- SR-021: HandleDeployArtifacts now dispatches an internal
  ApplyArtifactDataConnectionsToDcl message after the SQLite write so
  system-wide artifact-deploy data-connection changes go live
  immediately (was requiring a site restart).
- SnF-020: RetryParkedMessageAsync captures the parked row BEFORE the
  local write so a concurrent delete can't skip standby replication.

Sentinels / naming collisions:
- HM-021: CentralSiteId changed from "central" to "$central"
  (uncollideable — leading $ is forbidden in real SiteIdentifiers).

Doc / surface cleanups:
- SEL-018: FailedWriteCount promoted to ISiteEventLogger; XML softened
  to "Available for future Health Monitoring integration".
- SnF-019: VERIFY outcome — documented parking-after-DefaultMaxRetries
  in Component-StoreAndForward.md + DefaultMaxRetries XML (uniform
  cap; maxRetries:0 is the unbounded escape hatch).
- SnF-021: Component-StoreAndForward.md no longer claims the tracking
  table lives in SnF — it's in SiteRuntime, the interface is in Commons.
- CLI-020: bundle export response parse guarded with try/catch on
  JsonException / KeyNotFoundException / FormatException — emits a
  clean INVALID_RESPONSE exit instead of a stack trace.

Config:
- ClusterInfra-013: intent comment added to "catastrophic config" test.
- Host-016: appsettings.Site.json second CentralContactPoints entry
  removed (was pointing at the SITE's own port); doc-key explains how
  to extend.
- Host-018: NodeName added to both shipped per-role configs (was
  causing SourceNode to be null on audit rows).

UI:
- CentralUI-029: replaced JS.InvokeAsync<int>("eval", …) with an ES
  module import (new wwwroot/js/browser-time.js).
- CentralUI-032: AuditResultsGrid gains a Previous button backed by a
  cursor stack.

10+ new regression tests across the affected projects. Build clean;
all suites green. README regenerated: 6 open (was 33).

Session-to-date: 130 of 136 originally-open Theme findings closed.

tests/ScadaLink.Host.Tests/LoggerConfigurationTests.cs

@@ -108,4 +108,54 @@ public class LoggerConfigurationTests
         Assert.Equal(LogEventLevel.Warning, result);
         Assert.Empty(writer.ToString());
     }
+
+    /// <summary>
+    /// Host-020: <c>ScadaLink:Logging:MinimumLevel</c> is the documented source
+    /// of truth for the Serilog floor, and the explicit <c>MinimumLevel.Is</c>
+    /// call deliberately runs after <c>ReadFrom.Configuration(...)</c> so a
+    /// <c>Serilog:MinimumLevel</c> entry is overridden. To make that precedence
+    /// visible — instead of silently swallowed — <see cref="LoggerConfigurationFactory.Build(IConfiguration,string,string,string,TextWriter)"/>
+    /// writes a one-shot warning when both keys are present. The warning must
+    /// name both values and point the operator at the documented key. When the
+    /// Serilog key is absent the warning is silent.
+    /// </summary>
+    [Fact]
+    public void Build_BothMinimumLevelKeysSet_WarnsAboutOverride()
+    {
+        var writer = new StringWriter();
+        var configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["ScadaLink:Logging:MinimumLevel"] = "Warning",
+                ["Serilog:MinimumLevel"] = "Debug",
+            })
+            .Build();
+
+        LoggerConfigurationFactory.Build(configuration, "Central", "central", "node1", writer);
+
+        var warning = writer.ToString();
+        Assert.Contains("warning", warning, StringComparison.OrdinalIgnoreCase);
+        Assert.Contains("Serilog:MinimumLevel", warning);
+        Assert.Contains("ScadaLink:Logging:MinimumLevel", warning);
+        Assert.Contains("Debug", warning);
+        Assert.Contains("Warning", warning);
+    }
+
+    [Fact]
+    public void Build_OnlyScadaLinkMinimumLevelSet_NoOverrideWarning()
+    {
+        var writer = new StringWriter();
+        var configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["ScadaLink:Logging:MinimumLevel"] = "Warning",
+            })
+            .Build();
+
+        LoggerConfigurationFactory.Build(configuration, "Central", "central", "node1", writer);
+
+        // No Serilog override -> no override-warning. (The ScadaLink value is
+        // a recognised level, so ParseLevel is silent too.)
+        Assert.Empty(writer.ToString());
+    }
 }