release(v2.2.0): add storage explorer + disk usage scanner

public/api/pro/diskUsageTopFiles.php

@@ -0,0 +1,51 @@
+<?php
+// public/api/pro/diskUsageTopFiles.php
+declare(strict_types=1);
+
+header('Content-Type: application/json; charset=utf-8');
+
+require_once __DIR__ . '/../../../config/config.php';
+
+// Basic auth / admin check
+if (session_status() !== PHP_SESSION_ACTIVE) {
+    session_start();
+}
+
+$username = (string)($_SESSION['username'] ?? '');
+$isAdmin  = !empty($_SESSION['isAdmin']) || (!empty($_SESSION['admin']) && $_SESSION['admin'] === '1');
+
+if ($username === '' || !$isAdmin) {
+    http_response_code(403);
+    echo json_encode([
+        'ok'    => false,
+        'error' => 'Forbidden',
+    ]);
+    return;
+}
+
+@session_write_close();
+
+// Pro-only gate: require Pro active AND ProDiskUsage class
+if (!defined('FR_PRO_ACTIVE') || !FR_PRO_ACTIVE || !class_exists('ProDiskUsage')) {
+    http_response_code(403);
+    echo json_encode([
+        'ok'    => false,
+        'error' => 'FileRise Pro is not active on this instance.',
+    ]);
+    return;
+}
+
+$limit = isset($_GET['limit']) ? max(1, (int)$_GET['limit']) : 100;
+
+try {
+    $result = ProDiskUsage::getTopFiles($limit);
+    http_response_code(!empty($result['ok']) ? 200 : 404);
+    echo json_encode($result, JSON_UNESCAPED_SLASHES);
+} catch (Throwable $e) {
+    http_response_code(500);
+    echo json_encode([
+        'ok'      => false,
+        'error'   => 'internal_error',
+        'message' => $e->getMessage(),
+    ]);
+}