feat(dlp): graceful shutdown and COM cleanup for email collector

windows/email-outbound-collector.ps1

@@ -610,7 +610,8 @@ if ($useOutlook) {
 # Main loop
 # ---------------------------------------------------------------------------
 
-while ($true) {
+try {
+    while ($true) {
         try {
             Flush-Wal
             Write-CollectorHealth -Status 'running'
@@ -651,4 +652,23 @@ while ($true) {
         }
 
         Start-Sleep -Seconds $resolvedPollSeconds
+    }
+}
+finally {
+    Write-CollectorHealth -Status 'stopped'
+    try {
+        if ($null -ne $script:SentFolder) {
+            [void][System.Runtime.InteropServices.Marshal]::ReleaseComObject($script:SentFolder)
+            $script:SentFolder = $null
+        }
+        if ($null -ne $script:OutlookNamespace) {
+            [void][System.Runtime.InteropServices.Marshal]::ReleaseComObject($script:OutlookNamespace)
+            $script:OutlookNamespace = $null
+        }
+        if ($null -ne $script:OutlookApp) {
+            [void][System.Runtime.InteropServices.Marshal]::ReleaseComObject($script:OutlookApp)
+            $script:OutlookApp = $null
+        }
+    }
+    catch {}
 }