Never wait on the process tree when starting NetX.

Windows PowerShell 5.1 Start-Process -Wait (and `& exe` with captured
output) waits for every descendant / until the stdout pipe closes. The
postgres and NetX processes a start leaves running made runtime_ctl.ps1
never return: tray stuck on "Starting", Start Menu "Start NetX" never
opened the UI. Start-NetxPowerShell -Wait, the UAC relaunch and the Setup
wait in check_update now wait for the process itself (WaitForExit).

Service mode in runtime_ctl: start via sc.exe without blocking on
SERVICE_RUNNING; stop writes the supervisor stop flag, polls up to 120s,
then kills the WinSW tree as a last resort.

Verified in an offline Windows Sandbox (no VC++ redist, no Python).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packaging/runtime_ctl.ps1

@@ -16,19 +16,47 @@ $prog = Get-NetxProgramRoot -Override $ProgramRoot
 $data = Get-NetxDataRoot -ProgramRoot $prog -Override $DataRoot
 
 function Invoke-NetxChildScript([string]$Name, [string[]]$Extra = @()) {
-    & powershell.exe -NoProfile -ExecutionPolicy Bypass -File (Join-Path $PSScriptRoot $Name) `
-        -ProgramRoot $prog -DataRoot $data @Extra
-    return $LASTEXITCODE
+    # Never read the child's stdout: postgres / NetX processes it starts inherit the
+    # pipe, so `& powershell.exe` with captured output blocks until they exit (forever).
+    # Start-Process -Wait is no good either (it waits for the whole process tree).
+    $p = Start-NetxPowerShell -File (Join-Path $PSScriptRoot $Name) `
+        -Arguments (@("-ProgramRoot", $prog, "-DataRoot", $data) + $Extra) `
+        -WorkingDirectory $prog -WindowStyle Hidden -PassThru
+    $null = $p.Handle  # keep a handle so ExitCode is available after exit
+    $p.WaitForExit()
+    return $p.ExitCode
+}
+
+function Stop-NetxService {
+    # Stop-Service waits forever on a service that will not stop; poll with a deadline
+    # and kill the WinSW process tree as a last resort.
+    $svc = Get-Service -Name "NetX" -ErrorAction SilentlyContinue
+    if (-not $svc -or $svc.Status -eq "Stopped") { return }
+    # Ask service_run.ps1 to exit ourselves rather than relying only on WinSW's stop hook.
+    Write-NetxServiceStopFlag -DataRoot $data
+    & sc.exe stop NetX | Out-Null
+    $deadline = (Get-Date).AddSeconds(120)
+    while ((Get-Date) -lt $deadline) {
+        Start-Sleep -Seconds 1
+        $svc.Refresh()
+        if ($svc.Status -eq "Stopped") { return }
+    }
+    $wmi = Get-CimInstance Win32_Service -Filter "Name='NetX'" -ErrorAction SilentlyContinue
+    if ($wmi -and $wmi.ProcessId) { & taskkill.exe /PID $wmi.ProcessId /T /F | Out-Null }
+    $null = Invoke-NetxChildScript "stop_netx_app.ps1"
+}
+
+function Start-NetxService {
+    # Don't block on SERVICE_RUNNING: callers wait for /health instead.
+    $svc = Get-Service -Name "NetX" -ErrorAction SilentlyContinue
+    if ($svc -and $svc.Status -eq "Stopped") { & sc.exe start NetX | Out-Null }
 }
 
 $runner = Get-NetxManagedRunner
 switch ($runner) {
     "service" {
-        switch ($Action) {
-            "start" { Start-Service -Name "NetX" }
-            "stop" { Stop-Service -Name "NetX" -Force }
-            "restart" { Restart-Service -Name "NetX" -Force }
-        }
+        if ($Action -ne "start") { Stop-NetxService }
+        if ($Action -ne "stop") { Start-NetxService }
     }
     "task" {
         if ($Action -ne "start") {