fix(lab): avoid PostgreSQL pipeline deadlock [T-014]

Sense/scripts/t014-capacity.ps1

@@ -128,14 +128,23 @@ function Stop-ManagedProcess($Managed) {
 function Stop-AllManagedProcesses($Items) {
     $processes = @($Items | Where-Object { $null -ne $_ -and $null -ne $_.Process })
     foreach ($item in $processes) {
-        if (-not $item.Process.HasExited) {
-            $item.Process.Kill()
+        try {
+            if (-not $item.Process.HasExited) {
+                $item.Process.Kill()
+            }
+        }
+        catch {
+            if (-not $item.Process.HasExited) { throw }
         }
     }
-    foreach ($item in $processes) {
-        if (-not $item.Process.HasExited) {
-            $item.Process.WaitForExit(10000) | Out-Null
-        }
+    $cleanupWatch = [Diagnostics.Stopwatch]::StartNew()
+    while ($cleanupWatch.Elapsed.TotalSeconds -lt 10 -and
+        @($processes | Where-Object { -not $_.Process.HasExited }).Count -gt 0) {
+        Start-Sleep -Milliseconds 100
+    }
+    $remaining = @($processes | Where-Object { -not $_.Process.HasExited })
+    if ($remaining.Count -gt 0) {
+        Write-Warning "managed processes did not exit within the shared cleanup deadline: $($remaining.Count)"
     }
 }
 
@@ -607,7 +616,12 @@ try {
     New-Item -ItemType Directory -Path $pgData | Out-Null
     Invoke-Checked $script:initdb '-D' $pgData '-U' 'postgres' '-A' 'trust' '--encoding=UTF8' '--no-locale' '--no-sync'
     $serverOptions = "-h 127.0.0.1 -p $postgresPort -c listen_addresses=127.0.0.1"
-    Invoke-Checked $script:pgCtl '-D' $pgData '-l' $pgLog '-o' $serverOptions '-w' 'start'
+    # Do not pipe pg_ctl start output: postgres can inherit the pipeline handle and
+    # keep PowerShell waiting until the server exits.
+    & $script:pgCtl '-D' $pgData '-l' $pgLog '-o' $serverOptions '-w' 'start'
+    if ($LASTEXITCODE -ne 0) {
+        throw "required command failed with exit code $LASTEXITCODE"
+    }
     $postgresStarted = $true
     Invoke-Checked $script:psql '-X' '-v' 'ON_ERROR_STOP=1' '-d' $adminRootDSN '-f' (Join-Path $script:repoRoot 'deploy\postgres\001_roles.sql')
     Invoke-Checked $script:createdb '-h' '127.0.0.1' '-p' ([string]$postgresPort) '-U' 'postgres' $databaseName