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.

code-reviews/SiteRuntime/findings.md

@@ -8,7 +8,7 @@
 | Last reviewed | 2026-05-28 |
 | Reviewer | claude-agent |
 | Commit reviewed | `1eb6e97` |
-| Open findings | 5 |
+| Open findings | 3 |
 
 ## Summary
 
@@ -1038,9 +1038,11 @@ be gated on "no instance with this name is currently terminating".
 |--|--|
 | Severity | Medium |
 | Category | Design-document adherence |
-| Status | Open |
+| Status | Resolved |
 | Location | `src/ScadaLink.SiteRuntime/Actors/DeploymentManagerActor.cs:931` |
 
+**Resolution (2026-05-28):** Took the "refactor `EnsureDclConnections` into a shared field-based helper" path. Extracted a new `EnsureDclConnection(name, protocol, primaryJson, backupJson, failoverRetryCount)` method that owns the hash-cache check and the `CreateConnectionCommand` Tell — both the existing inline `EnsureDclConnections(configJson)` and the new artifact path now drive through it. `ComputeConnectionConfigHash` got a field-based overload so the artifact path (which carries data directly on `DataConnectionArtifact`) reuses the same hash logic as the `ConnectionConfig`-based inline path. To keep `_createdConnections` mutation actor-thread-confined (the artifact-deploy persistence runs inside a `Task.Run`), the off-thread persistence dispatches a new internal `ApplyArtifactDataConnectionsToDcl` message back to `Self` after the SQLite writes; the actor-thread handler then iterates and invokes `EnsureDclConnection`. The DCL only sees `CreateConnectionCommand` (no `Update`/`Delete` messages exist in the codebase, and `CreateConnectionCommand` is treated as upsert-by-name — same shape as the inline-config path). Build clean; 302 SiteRuntime tests green (the existing `EnsureDclConnections_ConnectionConfigChanged_ReissuesCreateCommand` regression test still passes through the refactored shared helper).
+
 **Description**
 
 `HandleDeployArtifacts` persists the artifact bundle (shared scripts, external
@@ -1088,9 +1090,11 @@ and artifact paths can drive through it.
 |--|--|
 | Severity | Medium |
 | Category | Code organization & conventions |
-| Status | Open |
+| Status | Resolved |
 | Location | `src/ScadaLink.SiteRuntime/Scripts/AuditingDbCommand.cs:138` |
 
+**Resolution (2026-05-28):** Took the recommended "expose a proper API surface" path (the SiteRuntime-006 precedent). Added an `internal DbConnection Inner => _inner;` accessor to `AuditingDbConnection`; both classes are `internal sealed` in the same assembly, so the accessor stays out of the public API. The `AuditingDbCommand.DbConnection` setter now unwraps an `AuditingDbConnection` via `auditing.Inner` instead of `Type.GetField("_inner", BindingFlags.NonPublic | BindingFlags.Instance)!.GetValue(...)`. No reflection, no `!.` null-forgiveness hiding a runtime crash, no static-analyzer/IL-trim noise — and the same module that enforces "no `System.Reflection` in scripts" no longer reflects internally. The getter's `_wrappingConnection ?? _inner.Connection` fallback was left as-is; addressing the `CreateDbCommand()` round-trip concern is a separate behavioural decision (the finding marked it secondary). Build clean; 302 SiteRuntime tests green.
+
 **Description**
 
 The `DbConnection` setter on `AuditingDbCommand` unwraps an