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/install.txt

@@ -0,0 +1,15 @@
+The FPDF library is made up of the following elements:
+
+- the main file, fpdf.php, which contains the class
+- the font definition files located in the font directory
+
+The font definition files are necessary as soon as you want to output some text in a document.
+If they are not accessible, the SetFont() method will produce the following error:
+
+FPDF error: Could not include font definition file
+
+
+Remarks:
+
+- Only the files corresponding to the fonts actually used are necessary
+- The tutorials provided in this package are ready to be executed