fix: updates_xml_build writes only the current channel entry

Was cascading entries for all lower channels on stable release,
producing wrong download URLs for non-existent channel releases.
Now writes only the entry for the current stability level;
the preserve logic retains entries from other channels.

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

cli/updates_xml_build.php

@@ -290,31 +290,30 @@ $allChannels = ['development', 'alpha', 'beta', 'rc', 'stable'];
 $stabilityIndex = array_search($stability === 'development' ? 'development' : $stability, $allChannels);
 if ($stabilityIndex === false) $stabilityIndex = 4; // default to stable
 
-// Write entries for this stability and all below it
+// Write only the current channel entry (not cascade)
+// Each channel release only creates its own entry; preserved entries handle other channels
 $entries = [];
-for ($i = 0; $i <= $stabilityIndex; $i++) {
-	$channelName = $allChannels[$i];
-	$channelSuffix = $stabilitySuffixMap[$channelName] ?? '';
-	$channelVersion = $version . $channelSuffix;
-	$channelTag = $stabilityTagMap[$channelName] ?? $channelName;
-	$channelDownloadUrl = "{$giteaUrl}/{$org}/{$repo}/releases/download/{$channelTag}/{$typePrefix}{$extElement}-{$channelVersion}.zip";
-	$channelInfoUrl = "{$giteaUrl}/{$org}/{$repo}/releases/tag/{$channelTag}";
+$channelName = $allChannels[$stabilityIndex];
+$channelSuffix = $stabilitySuffixMap[$channelName] ?? '';
+$channelVersion = $version . $channelSuffix;
+$channelTag = $stabilityTagMap[$channelName] ?? $channelName;
+$channelDownloadUrl = "{$giteaUrl}/{$org}/{$repo}/releases/download/{$channelTag}/{$typePrefix}{$extElement}-{$channelVersion}.zip";
+$channelInfoUrl = "{$giteaUrl}/{$org}/{$repo}/releases/tag/{$channelTag}";
 
-	$entries[] = buildEntry(
-		$channelName,
-		$channelVersion,
-		$channelDownloadUrl,
-		$extName,
-		$extElement,
-		$extType,
-		$clientTag,
-		$folderTag,
-		$channelInfoUrl,
-		$targetPlatform,
-		$phpTag,
-		$shaTag
-	);
-}
+$entries[] = buildEntry(
+	$channelName,
+	$channelVersion,
+	$channelDownloadUrl,
+	$extName,
+	$extElement,
+	$extType,
+	$clientTag,
+	$folderTag,
+	$channelInfoUrl,
+	$targetPlatform,
+	$phpTag,
+	$shaTag
+);
 
 // -- Preserve existing entries for channels not being updated -----------------
 $dest = $outputFile ?? "{$root}/updates.xml";