test+docs(m5): M5.7 — de-date 2 EndToEnd purge tests (closes #52); document T3-T8 in Component-AuditLog/-CLI/README/CLAUDE

Tests: anchor SeedOccurredAt() to a fixed thresholdAnchor (2026-01-20) and compute
RetentionDays dynamically (UtcNow - anchor + 1d) so the threshold always sits near
Jan 20 2026, between the Jan-15 "old" seed (purged) and Apr-15/Jun-15 "kept" seeds.
Seed dates stay within the explicit pf_AuditLog_Month boundary range (Jan 2026 –
Dec 2027) — relative-from-now offsets landed before 2026-01-01 (the catch-all
partition, invisible to GetPartitionBoundariesOlderThanAsync). Both tests confirmed
passing; all 284 AuditLog tests green.

Docs:
- Component-AuditLog.md: per-channel retention overrides (T3, PerChannelRetentionDays
  + bounded DELETE + AuditLogPurge:ChannelPurgeBatchSize); ParentExecutionId tag-cascade
  now spans alarm-triggered + nested CallScript/CallShared + inbound→routed (T4, "no
  further spawn points deferred"); per-node stuck KPIs for Notification Outbox +
  Site Call Audit (T6); T7 structured response-capture increments (request headers in
  Extra.requestHeaders, AuditInboundCeilingHits counter, per-method SkipBodyCapture);
  T8 CLI audit tree; T1 hash-chain + T2 Parquet explicitly marked deferred to v1.x.
- Component-CLI.md + README.md: document audit tree --execution-id <guid> and
  audit backfill-source-node --sentinel/--before/--batch with exact options verified
  against AuditCommands.cs; update Interactions to list new endpoints.
- CLAUDE.md: update audit-log design-decision bullets for T3 per-channel retention,
  T4 tag-cascade complete, T6 per-node KPIs, T7 inbound capture increments, T8 tree
  command; clarify T1/T2 remain deferred to v1.x.

CLAUDE.md

@@ -163,14 +163,16 @@ Related repos cloned as sibling directories under `~/Desktop/` — referenced fo
 - Scope = script trust boundary: outbound API (sync + cached), outbound DB (sync + cached), notifications, inbound API. Framework/internal traffic is explicitly excluded.
 - One row per lifecycle event; cached calls produce 4+ rows per operation (`Submitted`, `Forwarded`, `Attempted`, `Delivered`/`Parked`/`Discarded`).
 - `ExecutionId` (`uniqueidentifier NULL`) is the universal per-run correlation value — every audit row emitted by one script execution / inbound request shares it; `CorrelationId` remains the per-operation lifecycle id (NULL for sync one-shots).
-- `ParentExecutionId` (`uniqueidentifier NULL`) is the cross-execution spawn pointer — every row of a spawned run carries the spawner's `ExecutionId`; first cut bridges the inbound API → routed-site-script case (the routed run records the inbound request's `ExecutionId`; the inbound row stays top-level / NULL); `IX_AuditLog_ParentExecution` backs the filter + the recursive execution-tree walk; tag cascade deferred.
+- `ParentExecutionId` (`uniqueidentifier NULL`) is the cross-execution spawn pointer — every row of a spawned run carries the spawner's `ExecutionId`; bridges inbound API → routed-site-script, alarm-triggered on-trigger scripts, and nested `CallScript`/`CallShared` invocations; `IX_AuditLog_ParentExecution` backs the filter + the recursive execution-tree walk. Tag-cascade coverage is complete as of M5.4 (T4) — no further spawn points are deferred.
 - Site SQLite hot-path first, then gRPC telemetry to central; ingest is idempotent on `EventId`; periodic reconciliation pull as fallback when telemetry is lost.
 - Cached operations: site emits a single additively-extended `CachedCallTelemetry` packet carrying both audit events and operational state; central writes `AuditLog` + `SiteCalls` in one transaction.
-- Payload cap 8 KB by default / 64 KB on error rows; auth headers redacted by default; SQL parameter values captured by default; per-target redaction opt-in.
+- Payload cap 8 KB by default / 64 KB on error rows; auth headers redacted by default; SQL parameter values captured by default; per-target redaction opt-in. Inbound API: full verbatim capture up to `InboundMaxBytes` (default 1 MiB); request headers stored in `Extra.requestHeaders` (post-redaction); per-method `SkipBodyCapture` flag suppresses bodies while still recording headers + metadata; `AuditInboundCeilingHits` counter surfaced on health snapshot. (M5.3 T7)
 - Audit-write failure NEVER aborts the user-facing action — audit is best-effort, the action's own success/failure path is authoritative.
-- 365-day central retention with monthly partition-switch purge; 7-day site SQLite retention with a hard `ForwardState` invariant (no row purged until forwarded or reconciled).
-- Append-only enforced via DB roles (writer role has INSERT only, no UPDATE/DELETE); hash-chain tamper evidence and Parquet archival are deferred to v1.x.
+- 365-day central retention with monthly partition-switch purge; per-channel retention overrides (`AuditLog:PerChannelRetentionDays`) expire rows earlier than the global window via a bounded, batched row DELETE on the purge actor's maintenance path — values must be shorter than the global window (M5.5 T3); 7-day site SQLite retention with a hard `ForwardState` invariant (no row purged until forwarded or reconciled).
+- Append-only enforced via DB roles (writer role has INSERT only, no UPDATE/DELETE); hash-chain tamper evidence (T1) and Parquet archival (T2) are deferred to v1.x — not shipped in M5.
 - Node-of-origin is captured alongside site-of-origin: `SourceNode` (`varchar(64)` NULL) on `AuditLog`, `Notifications`, and `SiteCalls` — `node-a`/`node-b` for site rows (qualified by `SourceSiteId`/`SourceSite`), `central-a`/`central-b` for central direct-write rows. Stamped at the writing node, carried verbatim through telemetry + reconciliation, and indexed via `IX_AuditLog_Node_Occurred (SourceNode, OccurredAtUtc)` on `AuditLog`.
+- Per-node stuck KPIs (M5.3 T6): Notification Outbox and Site Call Audit expose `PerNodeNotificationKpiRequest`/`PerNodeSiteCallKpiRequest` messages that group stuck/parked/delivered counts by `SourceNode`, surfacing per-node breakdowns on the Health dashboard.
+- `audit tree --execution-id <guid>` CLI command (M5.3 T8) + `GET /api/audit/tree` endpoint — resolves any node to its chain root and renders the full execution tree; backed by `IAuditLogRepository.GetExecutionTreeAsync`.
 - Central UI: new top-level **Audit** nav group + Audit Log page, with drill-ins from Notifications, Site Calls, External Systems, Inbound API Keys, Sites, and Instances.
 
 ### Security & Auth