feat: UnraidCheckExec for calling unraidcheck from web components

* Added `UnraidCheckExec` class to handle execution of the unraidcheck script and return JSON responses.
* Updated the unraidcheck script to parse query parameters for better integration with web components.
* This change maintains separation of concerns between UnraidCheck and ReplaceKey functionalities.

emhttp/plugins/dynamix.plugin.manager/include/UnraidCheckExec.php

@@ -0,0 +1,42 @@
+<?php
+/**
+ * This file exists to maintain separation of concerns between UnraidCheck and ReplaceKey.
+ * Instead of combining both classes directly, we utilize the unraidcheck script which already
+ * handles both operations in a simplified manner.
+ * 
+ * It's called via the WebguiCheckForUpdate function in composables/services/webgui.ts of the web components.
+ * Handles WebguiUnraidCheckExecPayload interface parameters:
+ * - altUrl?: string
+ * - json?: boolean
+ */
+class UnraidCheckExec
+{
+    private const SCRIPT_PATH = '/usr/local/emhttp/plugins/dynamix.plugin.manager/scripts/unraidcheck';
+
+    private function setupEnvironment(): void
+    {
+        header('Content-Type: application/json');
+
+        $params = [
+            'json' => 'true',
+        ];
+        // allows the web components to determine the OS_RELEASES url
+        if (isset($_GET['altUrl']) && filter_var($_GET['altUrl'], FILTER_VALIDATE_URL)) {
+            $params['altUrl'] = $_GET['altUrl'];
+        }
+        // pass the params to the unraidcheck script for usage in UnraidCheck.php
+        putenv('QUERY_STRING=' . http_build_query($params));
+    }
+
+    public function execute(): string
+    {
+        $this->setupEnvironment();
+        $output = [];
+        exec(self::SCRIPT_PATH, $output);
+        return implode("\n", $output);
+    }
+}
+
+// Usage
+$checker = new UnraidCheckExec();
+echo $checker->execute();