Add elapsed run time, per-account results CSV, and a default config path

Summaries now show elapsed wall-clock time since the run started, and every
summary (interim and final) overwrites a results.csv (Object ID, UPN,
persona/status) next to the audit log, so an operator has a plain export
without parsing NDJSON. ConfigPath also now defaults to
./config/persona-engine.json instead of requiring -ConfigPath every run.

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

Invoke-PersonaEngine.ps1

@@ -27,7 +27,8 @@
 
 .PARAMETER ConfigPath
     Path to the JSON configuration. Validated through all four layers before any
-    connection is attempted (FR-002).
+    connection is attempted (FR-002). Defaults to ./config/persona-engine.json,
+    resolved against the current directory, when omitted.
 
 .PARAMETER UserObjectId
     Evaluate a single user instead of enumerating the tenant. The recommended first
@@ -73,9 +74,8 @@
 #>
 [CmdletBinding(SupportsShouldProcess = $true, ConfirmImpact = 'High')]
 param(
-    [Parameter(Mandatory)]
     [ValidateNotNullOrEmpty()]
-    [string] $ConfigPath,
+    [string] $ConfigPath = (Join-Path (Get-Location).Path 'config' 'persona-engine.json'),
 
     [guid] $UserObjectId,
 
@@ -162,6 +162,13 @@ try {
     $logPath = $OutputPath ? $OutputPath : ($configuredPath ? $configuredPath : $defaultLogPath)
     $auditParams = @{ Destination = $destination; Path = $logPath; State = $sinkState }
 
+    # Lives next to the audit log rather than under its own config key for path -
+    # one directory to point an operator at, not two. The file name alone is
+    # configurable because "results.csv" may collide with something else already
+    # written there.
+    $resultsFileName = $config.Logging.resultsFileName ? [string]$config.Logging.resultsFileName : 'results.csv'
+    $resultsPath = Join-Path (Split-Path -Parent $logPath) $resultsFileName
+
     # Tracing is enabled by -Debug or by configuration, and requires acknowledgement
     # in the configuration either way (VR-003, enforced in validation layer 4).
     $traceRequested = $PSBoundParameters.ContainsKey('Debug') -or
@@ -222,6 +229,8 @@ try {
         IsEnforcing     = $runConfirmed
         ShouldProcessGate = $gate
         Tracing         = $tracing
+        StartedUtc      = $startedUtc
+        ResultsPath     = $resultsPath
     }
     if ($UserObjectId -and $UserObjectId -ne [guid]::Empty) { $runParams['UserObjectId'] = $UserObjectId.ToString() }