fix: tiebreak_rules is already decoded array from Supabase JSONB

Supabase returns JSONB columns as native arrays, not JSON strings.
json_decode() on an array throws TypeError. Now checks if already array.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

modules/tournaments/views/_tiebreak_config.php

@@ -3,7 +3,8 @@
  * Tiebreak configuration with drag-to-reorder
  * Expects: $tournament
  */
-$currentTiebreaks = json_decode($tournament['tiebreak_rules'] ?? '["buchholz_cut_1","buchholz","sonneborn_berger"]', true);
+$rawTiebreaks = $tournament['tiebreak_rules'] ?? '["buchholz_cut_1","buchholz","sonneborn_berger"]';
+$currentTiebreaks = is_array($rawTiebreaks) ? $rawTiebreaks : (json_decode($rawTiebreaks, true) ?? ['buchholz_cut_1', 'buchholz', 'sonneborn_berger']);
 $availableTiebreaks = [
     'buchholz' => 'Buchholz',
     'buchholz_cut_1' => 'Buchholz Cut 1',