Sortable HTML tables, local-time toggle, and RFC 3339 dates everywhere

- All timestamps (last logon, password last set, whenCreated, report
  generation time) now emit as RFC 3339 UTC in both the Markdown
  report and raw JSON dump, for both the Python and PowerShell
  scripts.
- md_to_html.py: click any table header to sort ascending/descending
  (vanilla JS, numeric-aware); a "Show local time" toggle swaps every
  timestamp between UTC and the viewer's local offset, still RFC 3339.

src/Invoke-ADAudit.ps1

@@ -74,6 +74,11 @@ $UAC_DONT_REQ_PREAUTH        = 0x400000
 $now = Get-Date
 $staleCutoff = $now.AddDays(-$StaleDays)
 
+function ConvertTo-Rfc3339($DateTime) {
+    if (-not $DateTime) { return $null }
+    return $DateTime.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssZ")
+}
+
 # ---------------------------------------------------------------------------
 # Object type counts (whole subtree)
 # ---------------------------------------------------------------------------
@@ -92,7 +97,7 @@ $ous = Get-ADOrganizationalUnit -SearchBase $SearchBase -Filter * -Properties De
             DN          = $_.DistinguishedName
             Name        = $_.Name
             Description = $_.Description
-            Created     = $_.whenCreated
+            Created     = ConvertTo-Rfc3339 $_.whenCreated
             Depth       = ([regex]::Matches($_.DistinguishedName, "OU=")).Count
         }
     }
@@ -123,11 +128,11 @@ $users = Get-ADUser -SearchBase $SearchBase -Filter * -Properties $userProps @ad
         TrustedForDelegation      = [bool]($uac -band $UAC_TRUSTED_FOR_DELEGATION)
         KerberosPreAuthDisabled   = [bool]($uac -band $UAC_DONT_REQ_PREAUTH)
         AdminCount                = [bool]($_.adminCount -gt 0)
-        LastLogon                 = $lastLogon
+        LastLogon                 = ConvertTo-Rfc3339 $lastLogon
         NeverLoggedOn             = $neverLoggedOn -and $_.Enabled
         Stale                     = $stale
-        PasswordLastSet           = $_.PasswordLastSet
-        Created                   = $_.whenCreated
+        PasswordLastSet           = ConvertTo-Rfc3339 $_.PasswordLastSet
+        Created                   = ConvertTo-Rfc3339 $_.whenCreated
         GroupCount                = (@($_.MemberOf)).Count
     }
 }
@@ -148,9 +153,9 @@ $computers = Get-ADComputer -SearchBase $SearchBase -Filter * -Properties $compP
         OS            = $_.OperatingSystem
         OSVersion     = $_.OperatingSystemVersion
         Disabled      = -not $_.Enabled
-        LastLogon     = $lastLogon
+        LastLogon     = ConvertTo-Rfc3339 $lastLogon
         Stale         = $stale
-        Created       = $_.whenCreated
+        Created       = ConvertTo-Rfc3339 $_.whenCreated
     }
 }
 
@@ -169,7 +174,7 @@ $groups = Get-ADGroup -SearchBase $SearchBase -Filter * -Properties Description,
             MemberCount = $memberCount
             Empty       = ($memberCount -eq 0)
             Description = $_.Description
-            Created     = $_.whenCreated
+            Created     = ConvertTo-Rfc3339 $_.whenCreated
         }
     }
 
@@ -227,7 +232,7 @@ Add-Line "# Active Directory Audit Report"
 Add-Line ""
 Add-Line "- Search base: ``$SearchBase``"
 if ($Server) { Add-Line "- Domain controller: ``$Server``" }
-Add-Line "- Generated: $($now.ToUniversalTime().ToString("o"))"
+Add-Line "- Generated: $(ConvertTo-Rfc3339 $now)"
 Add-Line "- Stale-account threshold: $StaleDays days of inactivity"
 Add-Line ""