fix: backup download keys in preflight, not postflight

Joomla's package installer deletes and recreates update site rows
from the manifest BETWEEN preflight and postflight. By the time
postflight ran backupDownloadKeys(), the extra_query values were
already empty.

Moved the backup to preflight() via a class property. The restore
in postflight() now uses keys saved before Joomla touched them.

Authored-by: Moko Consulting
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

source/script.php

@@ -39,8 +39,16 @@ class Pkg_MokowaasInstallerScript
 	 * with no default, causing INSERT failures when Joomla's package installer
 	 * creates placeholder rows before processing sub-extension manifests.
 	 */
+	/** @var array Download keys saved before Joomla wipes update sites */
+	private array $savedDownloadKeys = [];
+
 	public function preflight($type, $parent)
 	{
+		// CRITICAL: backup download keys BEFORE Joomla's installer wipes update sites.
+		// Joomla deletes and recreates #__update_sites rows from the manifest
+		// between preflight and postflight, clearing extra_query (dlid).
+		$this->savedDownloadKeys = $this->backupDownloadKeys();
+
 		try
 		{
 			$db = Factory::getDbo();
@@ -95,17 +103,14 @@ class Pkg_MokowaasInstallerScript
 		// Mark MokoWaaS extensions as protected (prevents disable/uninstall at framework level)
 		$this->protectExtensions();
 
-		// Save download keys before any update site manipulation
-		$savedKeys = $this->backupDownloadKeys();
-
 		// Migrate all Moko update server URLs to new format
 		$this->migrateUpdateServerUrls();
 
 		// Clean up stale/duplicate update sites
 		$this->cleanupStaleUpdateSites();
 
-		// Restore download keys that were wiped by cleanup/migration
-		$this->restoreDownloadKeys($savedKeys);
+		// Restore download keys saved in preflight (before Joomla wiped them)
+		$this->restoreDownloadKeys($this->savedDownloadKeys);
 
 		// Fix orphaned update records (extension_id=0)
 		$this->fixUpdateRecords();