Add API endpoints and management pages for software versions and upgrade paths

- Implemented API endpoint for managing software versions in `products_software_versions.php`.
- Created management page for software version assignments in `products_software_assignments.php`.
- Developed upgrade paths management functionality in `products_software_upgrade_paths_manage.php`.
- Enhanced software version details page in `products_software_version.php`.
- Added form handling and validation for software version creation and updates in `products_software_version_manage.php`.
- Introduced pagination and filtering for software versions in `products_software_versions.php`.
- Implemented success message handling for CRUD operations across various pages.

api/v2/get/generate_download_token.php

@@ -0,0 +1,44 @@
+<?php
+defined($security_key) or exit;
+
+//------------------------------------------
+// Generate Download Token Helper
+// Allows authenticated users to generate download URL tokens server-side
+//------------------------------------------
+
+//Connect to DB
+$pdo = dbConnect($dbname);
+
+//NEW ARRAY
+$criterias = [];
+
+//Parse GET parameters
+if(isset($get_content) && $get_content != ''){
+    $requests = explode("&", $get_content);
+    foreach ($requests as $y){
+        $v = explode("=", $y);
+        $criterias[$v[0]] = $v[1];
+    }
+}
+
+// Validate required parameters
+if (!isset($criterias['sn']) || !isset($criterias['version_id'])) {
+    http_response_code(400);
+    echo json_encode(["error" => "MISSING_PARAMETERS", "message" => "sn and version_id required"]);
+    exit;
+}
+
+// Generate token
+$token = create_download_url_token($criterias['sn'], $criterias['version_id']);
+$download_url = "https://" . $_SERVER['SERVER_NAME'] . "/api.php/v2/get/software_download?token=" . $token;
+
+// Return token and download URL
+echo json_encode([
+    "success" => true,
+    "token" => $token,
+    "download_url" => $download_url,
+    "expires_in_seconds" => 900,
+    "serial_number" => $criterias['sn'],
+    "version_id" => $criterias['version_id']
+]);
+?>