fix(container): normalize build dates to utc

Ensure container image build timestamps are converted from PowerShell DateTime values into UTC ISO 8601 strings before they are returned or stored. This avoids ambiguous unspecified kinds and keeps timer-driven update checks and container management responses consistent.

Author: Zacgoose

Modules/CIPPCore/Public/Entrypoints/Timer Functions/Start-ContainerUpdateCheck.ps1

@@ -167,6 +167,11 @@ function Start-ContainerUpdateCheck {
                 }
             }
 
+            if ($RemoteBuildDate -is [datetime]) {
+                if ($RemoteBuildDate.Kind -eq [System.DateTimeKind]::Unspecified) { $RemoteBuildDate = [DateTime]::SpecifyKind($RemoteBuildDate, [System.DateTimeKind]::Utc) }
+                $RemoteBuildDate = $RemoteBuildDate.ToUniversalTime().ToString("yyyy-MM-dd'T'HH:mm:ss'Z'")
+            }
+
             $RunningVersion = $env:APP_VERSION
             $UpdateAvailable = $false
             if ($RemoteVersion -and $RunningVersion -and $RemoteVersion -ne $RunningVersion) {

Modules/CIPPHTTP/Public/Entrypoints/HTTP Functions/CIPP/Settings/Invoke-ExecContainerManagement.ps1

@@ -79,6 +79,11 @@ function Invoke-ExecContainerManagement {
             }
         }
 
+        if ($created -is [datetime]) {
+            if ($created.Kind -eq [System.DateTimeKind]::Unspecified) { $created = [DateTime]::SpecifyKind($created, [System.DateTimeKind]::Utc) }
+            $created = $created.ToUniversalTime().ToString("yyyy-MM-dd'T'HH:mm:ss'Z'")
+        }
+
         return [pscustomobject]@{
             Digest  = [string]$digest
             Version = [string]$version