fix: preserve Windows agent tasks during upgrades

agents/windows/tests/Test-MinerOpsInstaller.ps1

@@ -0,0 +1,60 @@
+$ErrorActionPreference = "Stop"
+$installer = Join-Path (Split-Path $PSScriptRoot -Parent) "install.ps1"
+$tokens = $null
+$parseErrors = $null
+[System.Management.Automation.Language.Parser]::ParseFile(
+    $installer, [ref]$tokens, [ref]$parseErrors
+) | Out-Null
+if ($parseErrors.Count -gt 0) {
+    throw "install.ps1 parser errors: $($parseErrors.Message -join '; ')"
+}
+
+$source = Get-Content -LiteralPath $installer -Raw
+function Assert-SourceContains {
+    param([Parameter(Mandatory)][string]$Pattern, [Parameter(Mandatory)][string]$Message)
+    if ($source -notmatch $Pattern) { throw $Message }
+}
+
+$runtimeMatch = [regex]::Match(
+    $source,
+    '(?s)\$RuntimeFiles\s*=\s*@\((?<files>.*?)\)'
+)
+if (!$runtimeMatch.Success) { throw "Runtime file allowlist was not found." }
+$runtimeFiles = $runtimeMatch.Groups["files"].Value
+foreach ($forbidden in @("agent-config.json", "agent-state.json", "logs", "backups")) {
+    if ($runtimeFiles -match [regex]::Escape($forbidden)) {
+        throw "$forbidden must not be a managed deployment target."
+    }
+}
+
+$preflight = $source.IndexOf('# Validate the complete source')
+$firstTargetChange = $source.IndexOf('New-Item -ItemType Directory')
+if ($preflight -lt 0 -or $preflight -gt $firstTargetChange) {
+    throw "Source preflight must happen before target changes."
+}
+
+Assert-SourceContains 'if \(\$null -ne \(Get-MinerOpsScheduledTask' `
+    "Existing task preservation guard is missing."
+Assert-SourceContains 'Preserving existing Scheduled Task' `
+    "Existing task preservation is not explicit."
+Assert-SourceContains 'ExtraArguments\s*=\s*"-Limit 0 -TimeoutMs 8000"' `
+    "Fresh enrichment task arguments are missing."
+Assert-SourceContains 'Stop-MinerOpsScheduledTaskForUpgrade' `
+    "Bounded main Agent stop behavior is missing."
+Assert-SourceContains '\$mainTaskWasRunning' `
+    "Main Agent prior running state is not represented."
+Assert-SourceContains 'Copy-Item[^\r\n]*\(Join-Path \$Backup \$name\)' `
+    "Rollback does not restore managed files from backup."
+Assert-SourceContains 'Unregister-ScheduledTask' `
+    "Rollback does not remove tasks created by a failed install."
+Assert-SourceContains 'could not restart restored MinerOpsAgent' `
+    "Rollback restart failure is not surfaced."
+
+if ($source -match 'Register-ScheduledTask[^\r\n]*-Force') {
+    throw "Installer must not force-overwrite Scheduled Tasks."
+}
+if ($source -match '(?i)agent_secret|api3_password|api3_account') {
+    throw "Installer must not inspect or print credentials."
+}
+
+Write-Host "MinerOps installer source safety tests passed."