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>

PSScriptAnalyzerSettings.psd1

@@ -0,0 +1,34 @@
+@{
+    Severity     = @('Error', 'Warning')
+
+    IncludeRules = @(
+        # Constitution Principle III: every state-changing function must support
+        # ShouldProcess, so -WhatIf reaches all of them.
+        'PSUseShouldProcessForStateChangingFunctions'
+        'PSShouldProcess'
+
+        # Principle V: no credential material in source.
+        'PSAvoidUsingPlainTextForPassword'
+        'PSAvoidUsingConvertToSecureStringWithPlainText'
+        'PSUsePSCredentialType'
+
+        # NFR-004 maintainability.
+        'PSUseApprovedVerbs'
+        'PSUseSingularNouns'
+        'PSAvoidUsingCmdletAliases'
+        'PSUseDeclaredVarsMoreThanAssignments'
+        'PSAvoidUsingPositionalParameters'
+
+        # NFR-008 portability: no Windows PowerShell-only constructs.
+        'PSUseCompatibleSyntax'
+    )
+
+    Rules        = @{
+        PSUseCompatibleSyntax = @{
+            Enable         = $true
+            # 7.2 is the floor because the Automation runtime version is unverified
+            # until Stage B (research.md V-5b).
+            TargetVersions = @('7.2')
+        }
+    }
+}