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/psr7/src/UriComparator.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace GuzzleHttp\Psr7;
+
+use Psr\Http\Message\UriInterface;
+
+/**
+ * Provides methods to determine if a modified URL should be considered cross-origin.
+ *
+ * @author Graham Campbell
+ */
+final class UriComparator
+{
+    /**
+     * Determines if a modified URL should be considered cross-origin with
+     * respect to an original URL.
+     *
+     * @return bool
+     */
+    public static function isCrossOrigin(UriInterface $original, UriInterface $modified)
+    {
+        if (\strcasecmp($original->getHost(), $modified->getHost()) !== 0) {
+            return true;
+        }
+
+        if ($original->getScheme() !== $modified->getScheme()) {
+            return true;
+        }
+
+        if (self::computePort($original) !== self::computePort($modified)) {
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * @return int
+     */
+    private static function computePort(UriInterface $uri)
+    {
+        $port = $uri->getPort();
+
+        if (null !== $port) {
+            return $port;
+        }
+
+        return 'https' === $uri->getScheme() ? 443 : 80;
+    }
+
+    private function __construct()
+    {
+        // cannot be instantiated
+    }
+}