docs+code: close Theme 1 — 24 design-doc / XML-doc drift findings

Doc/XML-comment drift + small adherence fixes across 17 modules. Highlights:
- Host-017: site CoordinatedShutdown ordering — SiteStreamGrpcServer gains
  CancelAllStreams() (refuse new streams, cancel active), wired into
  Program.cs site branch via ApplicationStopping.
- InboundAPI-021: ParentExecutionId now travels on RouteToGet/SetAttributes
  symmetric with RouteToCallRequest; RouteHelper stamps from _parentExecutionId.
- ClusterInfra-012: ClusterOptionsValidator now requires both seed nodes.
- Comm-018: SiteCommunicationActor.HeartbeatMessage.IsActive derived from
  cluster leader check (was hardcoded true).
- DM-020: reconciliation audit row attributes the current user, not prior deployer.
- SEL-019: EventLogPurgeService early-exits on standby via active-node check.
- Plus comment/XML-doc accuracy fixes across AuditLog, ConfigurationDatabase,
  NotificationOutbox, SiteRuntime, SiteCallAudit; doc refreshes for Component-
  Commons / -ManagementService / -CLI / -ExternalSystemGateway / -HealthMonitoring
  / -Transport / -ConfigurationDatabase; CD-023 index-name doc alignment.

11 new regression tests (RouteHelper x4, SiteStreamGrpcServer x2,
ClusterOptionsValidator x1, SiteCommunicationActor x1, DeploymentService x1,
EventLogPurgeService x3). Build clean (0 warnings); InboundAPI/Communication/
Host suites all green. README regenerated: 112 open (was 136).

docs/requirements/Component-ConfigurationDatabase.md

@@ -61,7 +61,7 @@ The configuration database stores all central system data, organized by domain a
 - **SiteCalls**: The central audit table for cached site calls — `ExternalSystem.CachedCall()` and `Database.CachedWrite()` — owned by the Site Call Audit component and a sibling of the `Notifications` table. One row per cached operation. Columns: `TrackedOperationId` (GUID, primary key — generated site-side at call time, used as the idempotency key), `SourceSite`, `Kind` (a `TrackedOperationKind` enum stored with values `ExternalCall` / `DatabaseWrite`), `TargetSummary` (external system + method for an `ExternalCall`, database connection name for a `DatabaseWrite`), `Status` (a `TrackedOperationStatus` enum stored with values `Pending`, `Retrying`, `Delivered`, `Parked`, `Failed`, `Discarded`), `RetryCount`, `LastError`, `Provenance` (source instance / script), `CreatedAtUtc`, `UpdatedAtUtc`, `TerminalAtUtc`. The table is populated **only** by Site Call Audit telemetry and reconciliation pulls — sites are the source of truth and the row is an eventually-consistent mirror, never written by a central dispatcher. Ingestion is **insert-if-not-exists** keyed on `TrackedOperationId`, then **upsert-on-newer-status**; the lifecycle is monotonic, so at-least-once and out-of-order telemetry are harmless. Indexed on `Status` and `SourceSite` for KPI computation and the Central UI query page. Terminal rows are removed by a daily purge job — see Scheduled Maintenance below. See Component-SiteCallAudit.md for the full lifecycle.
 
 ### Audit Log
-- **AuditLog**: The central, append-only audit table owned by the Audit Log component — one row per script-trust-boundary lifecycle event across all channels (outbound API calls, outbound DB writes/reads, notifications, and inbound API requests). Sibling of the `Notifications` and `SiteCalls` tables but distinct: `AuditLog` is the immutable history that observes the other subsystems, not an operational state store. Columns: `EventId` (`uniqueidentifier` primary key — generated at the originator, used as the idempotency key), `OccurredAtUtc` (`datetime2`), `IngestedAtUtc` (`datetime2`), `Channel` (`varchar(32)` — `ApiOutbound` / `DbOutbound` / `Notification` / `ApiInbound`), `Kind` (`varchar(32)` — channel-specific event kind), `CorrelationId` (`uniqueidentifier` NULL — `TrackedOperationId` for cached calls, `NotificationId` for notifications, request-id for inbound API), `SourceSiteId` (`varchar(64)` NULL), `SourceInstanceId` (`varchar(128)` NULL), `SourceScript` (`varchar(128)` NULL), `Actor` (`varchar(128)` NULL), `Target` (`varchar(256)` NULL), `Status` (`varchar(32)` — outcome of *this event*: `Success`, `TransientFailure`, `PermanentFailure`, `Enqueued`, `Retrying`, `Delivered`, `Parked`, `Discarded`), `HttpStatus` (`int` NULL), `DurationMs` (`int` NULL), `ErrorMessage` (`nvarchar(1024)` NULL), `ErrorDetail` (`nvarchar(max)` NULL), `RequestSummary` (`nvarchar(max)` NULL — truncated request payload, headers redacted), `ResponseSummary` (`nvarchar(max)` NULL — truncated response payload), `PayloadTruncated` (`bit`), `Extra` (`nvarchar(max)` NULL — channel-specific JSON for fields not promoted to columns). Indexes: `IX_AuditLog_OccurredAtUtc` (primary time-range index for global scans), `IX_AuditLog_Site_Occurred (SourceSiteId, OccurredAtUtc)` (per-site filters), `IX_AuditLog_Correlation (CorrelationId)` (drilldown from a single operation), `IX_AuditLog_Channel_Status_Occurred (Channel, Status, OccurredAtUtc)` (KPI / dashboard tiles), and `IX_AuditLog_Target_Occurred (Target, OccurredAtUtc)` ("what did we send to system X"). The primary key on `EventId` enforces idempotency — central ingest is `INSERT … WHERE NOT EXISTS`, so at-least-once telemetry and reconciliation retries collapse to a single row. **Monthly partitioning** on `OccurredAtUtc` from day one via partition function `pf_AuditLog_Month` and partition scheme `ps_AuditLog_Month`, with a filegroup-per-month rollover so that retention purge is a partition switch rather than a row-level delete. The partition-maintenance job that rolls the scheme forward and switches expired partitions is owned by the Audit Log component, not this component. The table is populated only by Audit Log writers (site telemetry, central direct-write, reconciliation pulls); central ingest is **insert-if-not-exists** keyed on `EventId`. See Component-AuditLog.md for the full lifecycle, payload-capture policy, and ingestion paths.
+- **AuditLog**: The central, append-only audit table owned by the Audit Log component — one row per script-trust-boundary lifecycle event across all channels (outbound API calls, outbound DB writes/reads, notifications, and inbound API requests). Sibling of the `Notifications` and `SiteCalls` tables but distinct: `AuditLog` is the immutable history that observes the other subsystems, not an operational state store. Columns: `EventId` (`uniqueidentifier` primary key — generated at the originator, used as the idempotency key), `OccurredAtUtc` (`datetime2`), `IngestedAtUtc` (`datetime2`), `Channel` (`varchar(32)` — `ApiOutbound` / `DbOutbound` / `Notification` / `ApiInbound`), `Kind` (`varchar(32)` — channel-specific event kind), `CorrelationId` (`uniqueidentifier` NULL — `TrackedOperationId` for cached calls, `NotificationId` for notifications, request-id for inbound API), `SourceSiteId` (`varchar(64)` NULL), `SourceInstanceId` (`varchar(128)` NULL), `SourceScript` (`varchar(128)` NULL), `Actor` (`varchar(128)` NULL), `Target` (`varchar(256)` NULL), `Status` (`varchar(32)` — outcome of *this event*: `Success`, `TransientFailure`, `PermanentFailure`, `Enqueued`, `Retrying`, `Delivered`, `Parked`, `Discarded`), `HttpStatus` (`int` NULL), `DurationMs` (`int` NULL), `ErrorMessage` (`nvarchar(1024)` NULL), `ErrorDetail` (`nvarchar(max)` NULL), `RequestSummary` (`nvarchar(max)` NULL — truncated request payload, headers redacted), `ResponseSummary` (`nvarchar(max)` NULL — truncated response payload), `PayloadTruncated` (`bit`), `Extra` (`nvarchar(max)` NULL — channel-specific JSON for fields not promoted to columns). Indexes: `IX_AuditLog_OccurredAtUtc` (primary time-range index for global scans), `IX_AuditLog_Site_Occurred (SourceSiteId, OccurredAtUtc)` (per-site filters), `IX_AuditLog_CorrelationId (CorrelationId)` (drilldown from a single operation), `IX_AuditLog_Channel_Status_Occurred (Channel, Status, OccurredAtUtc)` (KPI / dashboard tiles), and `IX_AuditLog_Target_Occurred (Target, OccurredAtUtc)` ("what did we send to system X"). The primary key on `EventId` enforces idempotency — central ingest is `INSERT … WHERE NOT EXISTS`, so at-least-once telemetry and reconciliation retries collapse to a single row. **Monthly partitioning** on `OccurredAtUtc` from day one via partition function `pf_AuditLog_Month` and partition scheme `ps_AuditLog_Month`, with a filegroup-per-month rollover so that retention purge is a partition switch rather than a row-level delete. The partition-maintenance job that rolls the scheme forward and switches expired partitions is owned by the Audit Log component, not this component. The table is populated only by Audit Log writers (site telemetry, central direct-write, reconciliation pulls); central ingest is **insert-if-not-exists** keyed on `EventId`. See Component-AuditLog.md for the full lifecycle, payload-capture policy, and ingestion paths.
 
 ### Inbound API
 - **API Keys**: Key definitions (name/label, key value, enabled flag).