CMS 2.0 - Theme engine, logging, admin improvements

Major changes:
- New ThemeManager with Twig templating and SCSS compilation
- Dynamic themes system (themes/default, themes/demo)
- LogManager with SQLite storage and syslog forwarding
- RequestLogger with static helper methods
- Admin UI overhaul (Bootstrap 5, dark mode)
- Admin config page with logging and theme settings
- Admin logs page with filters and search
- Removed legacy Mustache templates
- Removed test plugin and theme
- Composer dependencies: Twig, scssphp, CommonMark, MaxMind GeoIP

vendor/psr/http-factory/src/ResponseFactoryInterface.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace Psr\Http\Message;
+
+interface ResponseFactoryInterface
+{
+    /**
+     * Create a new response.
+     *
+     * @param int $code HTTP status code; defaults to 200
+     * @param string $reasonPhrase Reason phrase to associate with status code
+     *     in generated response; if none is provided implementations MAY use
+     *     the defaults as suggested in the HTTP specification.
+     *
+     * @return ResponseInterface
+     */
+    public function createResponse(int $code = 200, string $reasonPhrase = ''): ResponseInterface;
+}