Implement Stage A: rule engine, validation, audit, and safety gates

Completes 109 of 121 tasks. Every remaining task needs a tenant connection
(T055, T056, T101-T103) or an Azure Automation account (T115-T121).

  354 offline Pester tests      PASS
  Engine purity (Principle IV)  PASS
  Sanitization (SC-013)         PASS  (156 files)
  Graph module loaded in tests  none  (SC-008 holds)

What landed
  - Four-layer configuration validation with stable finding codes, covering
    every VR-002 and VR-003 condition, plus a 23-fixture invalid-config corpus
  - Run loop, audit records (NDJSON through a single sink), summaries,
    reconciliation, and exit codes 0-6
  - Persistence behind a single write-body builder whose result always has
    exactly one key
  - Invoke-PersonaEngine.ps1 and Edit-PersonaEngineConfig.ps1
  - Six docs, two pipelines, traceability matrix, V-5a and sanitization records

Three deviations from tasks.md, each recorded in its status block

  T033 is not in Resolve-UserPersona. evaluationErrorThreshold is run-level
  state and the rule engine is pure; a counter there would break Principle IV.
  It lives in New-PersonaRunCounter and is applied in the run loop.

  A new src/Engine/ layer holds Invoke-PersonaEngineRun. The entry script
  imports the manifest, which requires Microsoft.Graph.Authentication, so a
  loop living only inside it could not run on a machine without the Graph SDK
  and SC-004 could not be proven at all. The entry script is now a thin
  wrapper and what ships is what is tested.

  The invalid-config corpus is generated by a committed script, with the
  generated fixtures committed too, so a reviewer sees the fixture in the diff.

Defects found by running the code, not by reading it

  Group and role ID lists were double-wrapped: @(Get-PersonaGroupIdPage ...)
  around a comma-returned array collapsed every membership list into one
  bogus space-joined entry. That is a silent false non-match, exactly what
  FR-013 exists to prevent.

  A 403 whose status appears only in the exception message parsed as $null,
  which the retry policy treats as a transport error - five requests per
  account against a tenant already refusing. Status extraction now falls back
  to the message text, bounded to 400-599.

  The sanitization scan walked tracked files only, so it covered 34 of 156
  files and none of this phase's code. It now scans untracked non-ignored
  files too, and a negative control confirms it catches a planted leak.

  Test-Json reports one error per violating location, not first-failure-only
  as the V-5a draft claimed. Record and pin corrected.

Enforcement remains blocked on the V-4 security sign-off.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/TestData/Memberships/memberships.json

@@ -0,0 +1,111 @@
+{
+  "_comment": "Synthetic membership fixtures keyed by user fixtureId. Each record carries three independently-retrieved facets (RE-007). The 'transitive-failed' and 'all-failed' entries are the most important here: they are what prove an unknown lookup never becomes a false non-match (FR-013), and that a failure in one facet does not contaminate the others.",
+  "groups": {
+    "tier0": "00000000-0000-0000-0000-0000000000a0",
+    "serviceAccounts": "00000000-0000-0000-0000-0000000000b0",
+    "testAccounts": "00000000-0000-0000-0000-0000000000c0",
+    "restricted": "00000000-0000-0000-0000-0000000000d0"
+  },
+  "memberships": [
+    {
+      "fixtureId": "enabled-employee",
+      "directGroupObjectIds": [],
+      "transitiveGroupObjectIds": [],
+      "directoryRoleIds": [],
+      "allRetrieved": true
+    },
+    {
+      "fixtureId": "disabled-employee",
+      "directGroupObjectIds": [],
+      "transitiveGroupObjectIds": [],
+      "directoryRoleIds": [],
+      "allRetrieved": true
+    },
+    {
+      "fixtureId": "guest",
+      "directGroupObjectIds": [],
+      "transitiveGroupObjectIds": [],
+      "directoryRoleIds": [],
+      "allRetrieved": true
+    },
+    {
+      "fixtureId": "null-properties",
+      "directGroupObjectIds": [],
+      "transitiveGroupObjectIds": [],
+      "directoryRoleIds": [],
+      "allRetrieved": true
+    },
+    {
+      "fixtureId": "missing-properties",
+      "directGroupObjectIds": [],
+      "transitiveGroupObjectIds": [],
+      "directoryRoleIds": [],
+      "allRetrieved": true
+    },
+    {
+      "fixtureId": "mixed-case-properties",
+      "directGroupObjectIds": [],
+      "transitiveGroupObjectIds": [],
+      "directoryRoleIds": [],
+      "allRetrieved": true
+    },
+    {
+      "fixtureId": "contractor",
+      "directGroupObjectIds": [],
+      "transitiveGroupObjectIds": [],
+      "directoryRoleIds": [],
+      "allRetrieved": true
+    },
+    {
+      "fixtureId": "service-account",
+      "directGroupObjectIds": [
+        "00000000-0000-0000-0000-0000000000b0"
+      ],
+      "transitiveGroupObjectIds": [
+        "00000000-0000-0000-0000-0000000000b0"
+      ],
+      "directoryRoleIds": [],
+      "allRetrieved": true
+    },
+    {
+      "fixtureId": "breakglass",
+      "directGroupObjectIds": [
+        "00000000-0000-0000-0000-0000000000a0"
+      ],
+      "transitiveGroupObjectIds": [
+        "00000000-0000-0000-0000-0000000000a0"
+      ],
+      "directoryRoleIds": [
+        "<TIER0-ROLE-TEMPLATE-ID>"
+      ],
+      "allRetrieved": true
+    },
+    {
+      "fixtureId": "tier0-admin",
+      "directGroupObjectIds": [],
+      "transitiveGroupObjectIds": [
+        "00000000-0000-0000-0000-0000000000a0"
+      ],
+      "directoryRoleIds": [],
+      "allRetrieved": true
+    },
+    {
+      "fixtureId": "transitive-failed",
+      "directGroupObjectIds": [],
+      "transitiveGroupObjectIds": [],
+      "directoryRoleIds": [],
+      "directRetrieved": true,
+      "rolesRetrieved": true,
+      "transitiveFailureReason": "Graph 503 after 5 attempts"
+    },
+    {
+      "fixtureId": "all-failed",
+      "directGroupObjectIds": [],
+      "transitiveGroupObjectIds": [],
+      "directoryRoleIds": [],
+      "directFailureReason": "Graph 503 after 5 attempts",
+      "transitiveFailureReason": "Graph 503 after 5 attempts",
+      "rolesFailureReason": "Graph 503 after 5 attempts"
+    }
+  ]
+}