refactor(scripts): optimize system remediation and M365 export scripts

- teams: harden Classic Teams removal, protect New Teams, and clean HKU run keys
- dotnet: add bootstrapper EXE uninstall support and remove orphaned 3.1.* folders
- teams: add MSIX package targeting and version parsing for vulnerable New Teams builds
- m365: improve Graph SDK export speed, reuse sessions, and add null-safe handling

scripts/Remove-ClassicTeams.ps1

@@ -0,0 +1,135 @@
+#Requires -RunAsAdministrator
+
+<#
+.SYNOPSIS
+    Removes Classic Microsoft Teams and Teams Machine-Wide Installer.
+.DESCRIPTION
+    Stops Classic Teams processes, uninstalls the Machine-Wide Installer via MSI,
+    removes per-user Classic Teams installations, cleans residual files/registry run keys,
+    and verifies that New Teams (MSTeams) remains intact.
+#>
+
+$ErrorActionPreference = "Continue"
+
+Write-Host "Starting Classic Microsoft Teams cleanup..." -ForegroundColor Cyan
+
+# 1. Stop ONLY Classic Teams processes (preserve New Teams)
+Get-Process -Name "Teams" -ErrorAction SilentlyContinue | Stop-Process -Force -ErrorAction SilentlyContinue
+
+# Stop Update.exe processes originating specifically from Classic Teams directories
+Get-Process -Name "Update" -ErrorAction SilentlyContinue | Where-Object {
+    $_.Path -like "*\Microsoft\Teams\Update.exe"
+} | Stop-Process -Force -ErrorAction SilentlyContinue
+
+Start-Sleep -Seconds 3
+
+# 2. Remove Teams Machine-Wide Installer from HKLM registry
+$uninstallPaths = @(
+    "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*",
+    "HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\*"
+)
+
+$machineWideInstallers = foreach ($path in$uninstallPaths) {
+    Get-ItemProperty $path -ErrorAction SilentlyContinue \vert{} Where-Object {$_.DisplayName -eq "Teams Machine-Wide Installer"
+    }
+}
+
+foreach ($app in$machineWideInstallers) {
+    Write-Host "Found Teams Machine-Wide Installer: $($app.DisplayName) $($app.DisplayVersion)" -ForegroundColor Yellow
+
+    if ($app.UninstallString -match "\{[A-Fa-f0-9\-]{36}\}") {
+        $productCode =$Matches[0]
+        Write-Host "Uninstalling Machine-Wide Installer via MSI product code: $productCode" -ForegroundColor Cyan
+        Start-Process -FilePath "msiexec.exe" -ArgumentList "/x $productCode /qn /norestart" -Wait -NoNewWindow
+    }
+    elseif ($app.UninstallString) {
+        Write-Host "Uninstalling via UninstallString: $($app.UninstallString)" -ForegroundColor Cyan
+        if ($app.UninstallString -match "msiexec") {
+            $args =$app.UninstallString -replace "msiexec.exe", "" -replace "/I", "/x"
+            Start-Process -FilePath "msiexec.exe" -ArgumentList "$args /qn /norestart" -Wait -NoNewWindow
+        } else {
+            Start-Process -FilePath "cmd.exe" -ArgumentList "/c `"$($app.UninstallString)`" /quiet /norestart" -Wait -NoNewWindow
+        }
+    }
+}
+
+# 3. Clean per-user Classic Teams installations
+$usersRoot = Join-Path$env:SystemDrive "Users"
+$userProfiles = Get-ChildItem -Path $usersRoot -Directory -ErrorAction SilentlyContinue \vert{} Where-Object {$_.Name -notin @("Public", "Default", "Default User", "All Users", "defaultuser0")
+}
+
+foreach ($profile in$userProfiles) {
+    $localTeamsFolder = Join-Path$profile.FullName "AppData\Local\Microsoft\Teams"
+    $roamingTeamsFolder = Join-Path$profile.FullName "AppData\Roaming\Microsoft\Teams"
+    $updateExe = Join-Path$localTeamsFolder "Update.exe"
+
+    if (Test-Path $updateExe) {
+        Write-Host "Uninstalling Classic Teams for profile: $($profile.Name)" -ForegroundColor Cyan
+        Start-Process -FilePath $updateExe -ArgumentList "--uninstall -s" -Wait -ErrorAction SilentlyContinue
+        Start-Sleep -Seconds 2
+    }
+
+    # Remove residual AppData folders (both Local and Roaming)
+    foreach ($folder in @($localTeamsFolder,$roamingTeamsFolder)) {
+        if (Test-Path $folder) {
+            Write-Host "Removing directory: $folder" -ForegroundColor Yellow
+            Remove-Item -Path $folder -Recurse -Force -ErrorAction SilentlyContinue
+        }
+    }
+}
+
+# 4. Remove System-Wide ProgramData Leftovers
+$leftoverPaths = @(
+    "$env:ProgramData\Microsoft\Teams",
+    "$env:ProgramData\Microsoft\TeamsMachineInstaller",
+    "$env:ProgramData\Microsoft\TeamsCustomData"
+)
+
+foreach ($path in$leftoverPaths) {
+    if (Test-Path $path) {
+        Write-Host "Removing leftover ProgramData path: $path" -ForegroundColor Yellow
+        Remove-Item -Path $path -Recurse -Force -ErrorAction SilentlyContinue
+    }
+}
+
+# 5. Clean Startup Registry Run Keys across loaded user hives
+$hkuPath = "Registry::HKEY_USERS"
+Get-ChildItem -Path $hkuPath -ErrorAction SilentlyContinue | ForEach-Object {
+    $runKey = Join-Path$_.PSPath "Software\Microsoft\Windows\CurrentVersion\Run"
+    if (Test-Path $runKey) {
+        $val = Get-ItemProperty -Path$runKey -Name "com.squirrel.teams.teams" -ErrorAction SilentlyContinue
+        if ($val) {
+            Write-Host "Removing Classic Teams startup reg key from hive: $($_.PSChildName)" -ForegroundColor Yellow
+            Remove-ItemProperty -Path $runKey -Name "com.squirrel.teams.teams" -ErrorAction SilentlyContinue
+        }
+    }
+}
+
+# 6. Confirm New Teams (MSTeams) status
+$newTeams = Get-AppxPackage -Name "MSTeams" -AllUsers -ErrorAction SilentlyContinue
+
+if ($newTeams) {
+    Write-Host "New Teams (MSTeams) is installed:" -ForegroundColor Green
+    $newTeams | Select-Object Name, Version, PackageFullName | Format-Table -AutoSize | Out-String | Write-Host
+} else {
+    Write-Host "WARNING: New Teams (MSTeams) was not detected on this device." -ForegroundColor Red
+}
+
+# 7. Final Verification
+$remainingMachineWide = foreach ($path in$uninstallPaths) {
+    Get-ItemProperty $path -ErrorAction SilentlyContinue \vert{} Where-Object {$_.DisplayName -eq "Teams Machine-Wide Installer"
+    }
+}
+
+$remainingClassicFolders = foreach ($profile in$userProfiles) {
+    $localTeamsFolder = Join-Path$profile.FullName "AppData\Local\Microsoft\Teams"
+    if (Test-Path $localTeamsFolder) {$localTeamsFolder }
+}
+
+if ($remainingMachineWide -or$remainingClassicFolders) {
+    Write-Host "Cleanup completed, but some Classic Teams remnants remain." -ForegroundColor Red
+    exit 1
+} else {
+    Write-Host "Classic Teams and Teams Machine-Wide Installer cleanup completed successfully." -ForegroundColor Green
+    exit 0
+}