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>

specs/001-persona-engine/contracts/cli-edit-persona-engine-config.md

@@ -0,0 +1,90 @@
+# Contract: `Edit-PersonaEngineConfig.ps1`
+
+Configuration validation, interactive editing, synthetic rule testing, and pipeline enforcement
+(FR-023 – FR-026).
+
+## Signature
+
+```powershell
+[CmdletBinding(SupportsShouldProcess = $true)]
+param(
+    [Parameter(Mandatory)][string] $ConfigPath,
+    [Parameter()][switch] $ValidateOnly,
+    [Parameter()][switch] $NonInteractive,
+    [Parameter()][string] $SchemaPath,
+    [Parameter()][string] $OutputPath,
+    [Parameter()][switch] $TreatWarningsAsErrors,
+    [Parameter()][string] $TestDataPath
+)
+```
+
+## Parameter contract
+
+| Parameter | Behaviour |
+| --- | --- |
+| `-ConfigPath` | Required. Configuration to validate or edit. |
+| `-ValidateOnly` | Validate and report; never enter the editor. |
+| `-NonInteractive` | Pipeline mode. **MUST NOT prompt and MUST NOT hang** (SC-010). Returns an exit code. |
+| `-SchemaPath` | Override the shipped schema. |
+| `-OutputPath` | Save-As target; leaves the input file untouched. |
+| `-TreatWarningsAsErrors` | Escalates `Warning` findings to blocking (VR-005). |
+| `-TestDataPath` | Synthetic sample users for offline rule testing (FR-025). No tenant connectivity. |
+
+## Validation layers (VR-001, ordered, fail-fast between layers)
+
+| Layer | Mechanism | Example findings |
+| --- | --- | --- |
+| 1. Syntax | `ConvertFrom-Json` | Malformed JSON |
+| 2. Schema | `Test-Json -SchemaFile` (draft-07, OTD-005) | Missing required field, wrong type, bad enum |
+| 3. Semantic | PowerShell checks | Every condition in VR-002 |
+| 4. Safety | PowerShell checks | Every condition in VR-003 |
+
+A layer that produces `Error` findings stops the sequence — running semantic checks over a
+structurally invalid document yields noise, not signal.
+
+### Layer 2 error-handling requirement
+
+`Test-Json` reports schema failure by writing errors rather than returning `$false` in several
+PowerShell versions. The wrapper MUST invoke it with `-ErrorAction SilentlyContinue -ErrorVariable`
+and convert collected errors into `ValidationFinding` objects, so layer 2 emits the same structured
+shape as every other layer (VR-004).
+
+## Finding contract
+
+Every finding carries `Severity`, `Code`, `Location` (JSON path or rule ID), `Description`,
+`SuggestedResolution`, and `Layer`. Finding codes are stable and namespaced by layer:
+
+```text
+PE-SYN-nnn   syntax
+PE-SCH-nnn   schema
+PE-SEM-nnn   semantic  (one code per VR-002 condition)
+PE-SAF-nnn   safety    (one code per VR-003 condition)
+```
+
+Stability matters: pipelines and runbooks will match on these codes.
+
+## Exit codes
+
+| Code | Condition |
+| --- | --- |
+| `0` | Valid; no blocking findings |
+| `1` | One or more `Error` findings |
+| `2` | `Warning` findings present with `-TreatWarningsAsErrors` |
+| `3` | Configuration file not found or unreadable |
+| `4` | Schema file not found or itself invalid |
+
+## Save contract (FR-026)
+
+1. Re-validate the edited document in full.
+2. Block the save on any `Error` finding.
+3. Write a timestamped backup — or require `-OutputPath` — before replacing an existing file.
+4. Overwriting the only valid configuration without a backup is a safety finding (VR-003), not
+   merely a warning.
+
+## Invariants (test-asserted)
+
+| Invariant | Assertion |
+| --- | --- |
+| Non-interactive never prompts | Runs to completion with stdin closed; no prompt, no hang (SC-010) |
+| Every VR-002/VR-003 condition detected | One test per condition, each asserting code, severity, and location (SC-009) |
+| Offline | Full validation and synthetic rule testing complete with no network access (SC-008) |