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/setasign/fpdf/README.md

@@ -0,0 +1,21 @@
+# FPDF
+**This repository is only made for cloning official FPDF releases which are available at: http://www.fpdf.org**
+**THERE WILL BE NO DEVELOPMENT IN THIS REPOSITORY!**
+
+FPDF is a PHP class which allows to generate PDF files with pure PHP. F from FPDF stands for Free: you may use it for any kind of usage and modify it to suit your needs.
+
+## Installation with [Composer](https://packagist.org/packages/setasign/fpdf)
+
+If you're using Composer to manage dependencies, you can use
+
+    $ composer require setasign/fpdf:^1.8
+
+or you can include the following in your composer.json file:
+
+```json
+{
+    "require": {
+        "setasign/fpdf": "^1.8"
+    }
+}
+```