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/ralouphie/getallheaders/composer.json

@@ -0,0 +1,26 @@
+{
+	"name": "ralouphie/getallheaders",
+	"description": "A polyfill for getallheaders.",
+	"license": "MIT",
+	"authors": [
+		{
+			"name": "Ralph Khattar",
+			"email": "ralph.khattar@gmail.com"
+		}
+	],
+	"require": {
+		"php": ">=5.6"
+	},
+	"require-dev": {
+		"phpunit/phpunit": "^5 || ^6.5",
+		"php-coveralls/php-coveralls": "^2.1"
+	},
+	"autoload": {
+		"files": ["src/getallheaders.php"]
+	},
+	"autoload-dev": {
+		"psr-4": {
+			"getallheaders\\Tests\\": "tests/"
+		}
+	}
+}