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/guzzlehttp/guzzle/Dockerfile

@@ -0,0 +1,18 @@
+FROM composer:latest as setup
+
+RUN mkdir /guzzle
+
+WORKDIR /guzzle
+
+RUN set -xe \
+    && composer init --name=guzzlehttp/test --description="Simple project for testing Guzzle scripts" --author="Márk Sági-Kazár <mark.sagikazar@gmail.com>" --no-interaction \
+    && composer require guzzlehttp/guzzle
+
+
+FROM php:7.3
+
+RUN mkdir /guzzle
+
+WORKDIR /guzzle
+
+COPY --from=setup /guzzle /guzzle