feat: add videodb media index with Docker stack

- Add videodb PHP/MySQL media collection manager (Blu-ray, DVD, CD)
- Dockerfile: PHP 8.1 + Apache with GD/mysqli/exif extensions
- docker-compose.yml: app on port 6761 + MySQL 8.0 with health checks
- docker-entrypoint.sh: auto-generates config.inc.php from env vars,
  waits for MySQL, initializes DB schema idempotently
- init-db.php: CLI schema installer using app's own prefix_query() logic
- Persistent volumes for DB, cache, and cover images

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

videodb/vendor/symfony/polyfill-intl-normalizer/bootstrap.php

@@ -0,0 +1,19 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Symfony\Polyfill\Intl\Normalizer as p;
+
+if (!function_exists('normalizer_is_normalized')) {
+    function normalizer_is_normalized($input, $form = p\Normalizer::NFC) { return p\Normalizer::isNormalized($input, $form); }
+}
+if (!function_exists('normalizer_normalize')) {
+    function normalizer_normalize($input, $form = p\Normalizer::NFC) { return p\Normalizer::normalize($input, $form); }
+}