Verify recorder identity once and retain original native process handles

tools/android/final-common.ps1

@@ -142,7 +142,7 @@ function StartAudio([string]$Name,[int]$Seconds) {
     if (Test-Path -LiteralPath $readyPath) { Remove-Item -LiteralPath $readyPath }
     $args=@('-NoProfile','-File',(Join-Path $PSScriptRoot 'record-native-audio.ps1'),'-OutputPath',(Join-Path $EvidenceDir "$Name.wav"),'-Seconds',"$Seconds",'-Serial',$Serial)
     $process=Start-Process pwsh -ArgumentList ($args | ForEach-Object {'"'+$_+'"'}) -WindowStyle Hidden -RedirectStandardOutput (Join-Path $EvidenceDir "$Name.stdout") -RedirectStandardError (Join-Path $EvidenceDir "$Name.stderr") -PassThru
-    $recorders.Add(@{name=$Name;process=$process;seconds=$Seconds;startedUtc=[DateTime]::UtcNow})
+    $recorders.Add(@{name=$Name;process=$process;seconds=$Seconds;nativeProcess=$null;startedUtc=[DateTime]::UtcNow})
     $readyPath=Join-Path $EvidenceDir "$Name.wav.ready.json"
     $ready=$false
     for ($attempt=0; $attempt -lt 120; $attempt++) {
@@ -151,6 +151,11 @@ function StartAudio([string]$Name,[int]$Seconds) {
         Start-Sleep -Milliseconds 100
     }
     Check "audio-ready-$Name" $ready 'Recorder reported actual Recording started before interaction'
+    $readyRecord=Get-Content -LiteralPath $readyPath -Raw|ConvertFrom-Json
+    $native=Get-Process -Id $readyRecord.recorderPid -ErrorAction Stop
+    Check "audio-native-identity-$Name" ($native.ProcessName-eq'scrcpy'-and$native.StartTime.ToUniversalTime()-ge$recorders[-1].startedUtc-and$native.StartTime.ToUniversalTime()-le([DateTime]$readyRecord.readyUtc).ToUniversalTime()) 'Own scrcpy created in this recording window; retain Process object rather than recycled PID lookup'
+    $native.Handle|Out-Null # Retain this native process handle through its exit, even if Windows reuses its PID.
+    $recorders[-1].nativeProcess=$native
     for ($attempt=0; $attempt -lt 20; $attempt++) {
         Adb @('shell','cmd','audio','set-volume','3','15') | Out-Null
         $route=Adb @('shell','dumpsys','audio')