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/templates/elegant/test.html

@@ -0,0 +1,29 @@
+<script language="JavaScript" type="text/javascript" src="../../javascript/prototype/prototype.js"></script>
+<script language="JavaScript" type="text/javascript" src="../../javascript/prototype/control.modal.js"></script>
+
+<style>
+#modal_container {
+    padding:5px;
+    background-color:#fff;
+    border:1px solid #666;
+    overflow:auto;
+    font-family:"Lucida Grande",Verdana;
+    font-size:12px;
+    color:#333;
+    text-align:left;
+}
+
+#modal_overlay {
+    background-color:#000;
+}
+</style>
+
+<a href="#contents" id="caller">click me</a>
+
+<div id="contents">
+	modal
+</div>
+
+<script>
+	new Control.Modal('caller');
+</script>