feat(audit): persist phase0 backend drift report artifacts

docs/plans/state.json

@@ -215,6 +215,25 @@
       ],
       "test_status": "pnpm test:run src/audit/phase0BaselineDrift.test.ts + pnpm audit:phase0-baseline:live:drift + pnpm typecheck passing"
     },
+    "phase0-live-baseline-backend-drift-artifacts": {
+      "status": "completed",
+      "date": "2026-02-27",
+      "updated": "2026-02-27",
+      "summary": "Extended backend drift checks to persist cadence artifacts by default (`phase0_baseline_live_backend_drift_<UTC-date>.md/.json`) via `--write-default-artifacts`, wired package scripts accordingly, and generated the first drift artifact set.",
+      "files_modified": [
+        "scripts/check-phase0-baseline-backend-drift.ts",
+        "package.json",
+        "README.md",
+        "docs/api/PROTOCOL.md",
+        "docs/architecture/AGENT_DIAGRAM.md",
+        "docs/architecture/GATEWAY_SESSIONS_AND_QUEUE.md",
+        "docs/plans/2026-02-25-phase0-instrumentation-ticket-checklist.md",
+        "docs/plans/artifacts/phase0_baseline_live_backend_drift_2026-02-27.md",
+        "docs/plans/artifacts/phase0_baseline_live_backend_drift_2026-02-27.json",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm audit:phase0-baseline:live:drift + pnpm test:run src/audit/phase0BaselineDrift.test.ts + pnpm typecheck passing"
+    },
     "phase0-instrumentation-ticket-checklist": {
       "status": "completed",
       "date": "2026-02-25",
@@ -7400,8 +7419,8 @@
     "deeper_surfaces_phase0_ticket_02": "completed — gateway + daemon routing emit run lifecycle/cancel telemetry and reaction match/skip audit events with filter summaries and cancellation latency, plus focused tests",
     "deeper_surfaces_phase0_ticket_03": "completed — gateway metrics now track run-state outcomes, cancel latency samples, and reaction decision counters with routing/gateway emitters",
     "deeper_surfaces_phase0_ticket_04": "completed — added phase-0 baseline summary tooling for run outcomes, cancel latency, and reaction decisions with markdown/json CLI output",
-    "deeper_surfaces_phase0_ticket_05": "completed — documented phase-0 telemetry fields/workflow, refreshed architecture/protocol docs, generated anonymized live baseline artifacts for channel/gateway/backend-scoped (pi/native) windows, and added backend artifact freshness/drift gates (`pnpm audit:phase0-baseline:live:drift`)",
-    "next_up": "Run scheduled `pnpm audit:phase0-baseline:live:refresh:drift` in each active environment and observe at least one full cadence cycle before tightening drift thresholds or changing additional run-control/reaction semantics.",
+    "deeper_surfaces_phase0_ticket_05": "completed — documented phase-0 telemetry fields/workflow, refreshed architecture/protocol docs, generated anonymized live baseline artifacts for channel/gateway/backend-scoped (pi/native) windows, and added backend artifact freshness/drift gates with persisted drift reports (`phase0_baseline_live_backend_drift_<UTC-date>.{md,json}`)",
+    "next_up": "Run scheduled `pnpm audit:phase0-baseline:live:refresh:drift` in each active environment and collect at least one additional UTC-date drift artifact so baseline-vs-prior comparisons become active before tightening thresholds or changing additional run-control/reaction semantics.",
     "pi_embedded_canary_spike": "completed — added optional pi_embedded backend adapter, canary-safe no-tools routing guard, backend success/fallback latency audit events, and docs/diagram updates while native remains default",
     "pi_embedded_evaluation_phase": "completed — final decision rollback (applied in runtime config): Window A failed latency/fallback gates (p50 +259ms, p95 +5695ms, fallback 25%, categories: pi_module_interface/empty_assistant_text); Window B remained sample-insufficient; controlled probes verified guard coverage (pi_no_tools_mode/capability_query/attachments_present each hit once)",
     "pi_embedded_manual_mode": "completed — added persisted runtime backend controls for manual Pi activation/deactivation (`/runtime` preferred, `/backend` alias; `status`, `activate pi`, `deactivate pi`, `use config`) while keeping config-driven default routing",