fix: UTF-8 BOM in update SQL files causing MariaDB syntax error

PowerShell 5.1 Out-File -Encoding UTF8 adds BOM (EF BB BF) which
breaks SQL execution on production. Also fix manifest JSON serializing
full PS objects instead of plain strings.

- build-update.ps1: use UTF8Encoding($false) for all file writes
- build-update.ps1: force .ToString() on Get-Content results
- UpdateRepository.php: strip BOM and normalize line endings in executeSql
- Rebuild ver_0.304 package files (clean SQL + manifest)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

autoload/Domain/Update/UpdateRepository.php

@@ -416,7 +416,12 @@ class UpdateRepository
             return $log;
         }
 
-        $queries = explode( PHP_EOL, $response );
+        // Usunięcie UTF-8 BOM i normalizacja końców linii
+        $response = ltrim( $response, "\xEF\xBB\xBF" );
+        $response = str_replace( "\r\n", "\n", $response );
+        $response = str_replace( "\r", "\n", $response );
+
+        $queries = explode( "\n", $response );
         $log[] = '[OK] Pobrano ' . count( $queries ) . ' zapytań SQL';
         $success = 0;
         $errors = 0;