fix: preserve Windows agent tasks during upgrades

scripts/test-windows-agent-source.sh

@@ -3,6 +3,7 @@ set -euo pipefail
 
 service="agents/windows/MinerOpsAgentService.ps1"
 control="agents/windows/MinerOpsControl.ps1"
+installer="agents/windows/install.ps1"
 rg -q 'X-MinerOps-Agent-ID' "${service}"
 ! rg -q 'commands/pending\?agent_id=' "${service}"
 ! rg -q 'DefaultValue "super"' "${service}"
@@ -13,9 +14,20 @@ for secret_field in 'api3_password =' 'api3_account =' 'raw_vendor' 'salt_respon
     ! rg -q "${secret_field}" "${control}"
 done
 
+rg -q 'Get-MinerOpsScheduledTask' "${installer}"
+rg -q 'Stop-MinerOpsScheduledTaskForUpgrade' "${installer}"
+rg -q 'mainTaskWasRunning' "${installer}"
+rg -q 'Preserving existing Scheduled Task' "${installer}"
+rg -q -- '-Limit 0 -TimeoutMs 8000' "${installer}"
+rg -q 'Unregister-ScheduledTask' "${installer}"
+rg -q 'could not restart restored MinerOpsAgent' "${installer}"
+! rg -q 'Register-ScheduledTask.*-Force' "${installer}"
+! rg -q 'agent_secret|api3_password|api3_account' "${installer}"
+
 if command -v pwsh >/dev/null 2>&1; then
     pwsh -NoProfile -File agents/windows/tests/Test-MinerOpsControl.ps1
+    pwsh -NoProfile -File agents/windows/tests/Test-MinerOpsInstaller.ps1
 else
-    echo "pwsh is not installed; deterministic PowerShell harness retained but not executed."
+    echo "pwsh is not installed; deterministic PowerShell harnesses retained but not executed."
 fi
 echo "Windows Agent source contract checks passed."