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/.htaccess

@@ -0,0 +1,39 @@
+#
+# Apache access control 
+#
+# @author Andreas Goetz <cpuidle@gmx.de>
+# $Id: .htaccess,v 1.2 2008/04/29 13:32:48 andig2 Exp $
+#
+
+# Don't show directory listings for URLs which map to a directory.
+Options -Indexes
+
+# go directly to index.php
+DirectoryIndex index.php
+
+# make sure Apache doesn't set default charset on it's own (bug 1943523)
+AddDefaultCharset utf-8
+
+# PHP 4, Apache 1.
+<IfModule mod_php4.c>
+  php_value default_charset utf-8
+</IfModule>
+
+# PHP 4, Apache 2.
+<IfModule sapi_apache2.c>
+  php_value default_charset utf-8
+</IfModule>
+
+# PHP 5, Apache 1 and 2.
+<IfModule mod_php5.c>
+  php_value default_charset utf-8
+</IfModule>
+
+# enable compression
+<IfModule mod_deflate_DISABLED.c>
+	# Deflate zum zippen
+	AddOutputFilterByType DEFLATE text/html text/plain text/xml application/xml application/xhtml+xml text/javascript text/css
+	BrowserMatch ^Mozilla/4 gzip-only-text/html
+	BrowserMatch ^Mozilla/4.0[678] no-gzip
+	BrowserMatch \bMSIE !no-gzip !gzip-only-text/html
+</IfModule>