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/default/setup.tpl

@@ -0,0 +1,32 @@
+{*
+  The configuration template
+  $Id: setup.tpl,v 2.11 2010/02/14 12:25:12 andig2 Exp $
+*}
+
+
+
+<table width="100%" >
+  <tr>
+    <td align="right">
+      <form action="setup.php" style="display:inline">
+        <input type="hidden" name="cacheempty" value="1" />
+        <input type="submit" value="{$lang.cacheempty}" class="editcaption" onclick="return(confirm('{$lang.really_del|escape:javascript|escape}?'))" />
+      </form>
+	  <form action="users.php" style="display:inline"><input type="submit" value="{$lang.help_usermanagern}" class="button"/></form>
+	</td>
+  </tr>
+</table>
+
+<form method="post" action="setup.php">
+<input type="hidden" name="save" value="1" />
+<table width="100%" class="tableborder">
+  {include file="options.tpl"}
+</table>
+
+<br />
+<div align="center">
+  <input type="submit" value="{$lang.save}" accesskey="s" />
+</div>
+<br />
+
+</form>