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/javascript/show.js

@@ -0,0 +1,13 @@
+/**
+ * Show logic
+ *
+ * @package JavaScript
+ * @author  Andreas Goetz	<cpuidle@gmx.de>
+ * @version $Id: show.js,v 1.1 2007/08/08 19:01:29 andig2 Exp $
+ */
+
+function showTrailer(title)
+{
+	open('trailer.php?title=' + escape(title), 'trailer',
+		 'width=500,height=500,menubar=no,resizable=yes,scrollbars=yes,status=yes,toolbar=no');
+}