feat(pay): zibll-style pay_modo/points/pay_limit, VIP quota, and local speed stream

Expand post pay meta with cash/points modes and member purchase limits,
enforce free-download daily quotas, and stream local files with VIP speed
caps while keeping remote links on redirect.

inc/classes/class-aksrt-download.php

@@ -284,11 +284,101 @@ class AKSRT_Download {
             update_post_meta((int) $row['post_id'], '_aksrt_res_download_count', $count + 1);
         }
 
+        $target_url = esc_url_raw((string) $meta['downloads'][$idx]['url']);
+        $speed_kb = 0;
+        $uid_speed = (int) ($row['user_id'] ?? 0);
+        if ($uid_speed > 0 && function_exists('aksrt_get_user_download_speed')) {
+            $speed_kb = aksrt_get_user_download_speed($uid_speed);
+        }
+
+        // Local attachment / uploads file: optional throttled stream (Zibll speed limit).
+        $local_path = $this->resolve_local_download_path($target_url);
+        if ($local_path !== '' && is_readable($local_path)) {
+            $this->stream_local_file($local_path, $speed_kb);
+            exit;
+        }
+
         nocache_headers();
-        wp_redirect(esc_url_raw((string) $meta['downloads'][$idx]['url']), 302);
+        wp_redirect($target_url, 302);
         exit;
     }
 
+    /**
+     * Map a site-local URL to a filesystem path under uploads (or ABSPATH).
+     */
+    private function resolve_local_download_path(string $url): string {
+        if ($url === '') {
+            return '';
+        }
+        $uploads = wp_upload_dir();
+        $baseurl = trailingslashit((string) ($uploads['baseurl'] ?? ''));
+        $basedir = trailingslashit((string) ($uploads['basedir'] ?? ''));
+        if ($baseurl !== '' && str_starts_with($url, $baseurl)) {
+            $rel = substr($url, strlen($baseurl));
+            $path = $basedir . ltrim(rawurldecode($rel), '/\\');
+            $real = realpath($path);
+            $root = realpath($basedir);
+            if ($real && $root && str_starts_with($real, $root) && is_file($real)) {
+                return $real;
+            }
+        }
+        // Same-host path under ABSPATH.
+        $home = trailingslashit(home_url('/'));
+        if (str_starts_with($url, $home)) {
+            $rel = substr($url, strlen($home));
+            $path = ABSPATH . ltrim(rawurldecode($rel), '/\\');
+            $real = realpath($path);
+            $root = realpath(ABSPATH);
+            if ($real && $root && str_starts_with($real, $root) && is_file($real)) {
+                return $real;
+            }
+        }
+        return '';
+    }
+
+    /**
+     * Stream a local file with optional KB/s throttle.
+     */
+    private function stream_local_file(string $path, int $speed_kb = 0): void {
+        $filename = basename($path);
+        $size = filesize($path);
+        if ($size === false) {
+            $this->fail_410();
+        }
+
+        nocache_headers();
+        header('Content-Description: File Transfer');
+        header('Content-Type: application/octet-stream');
+        header('Content-Disposition: attachment; filename="' . rawurlencode($filename) . '"');
+        header('Content-Transfer-Encoding: binary');
+        header('Content-Length: ' . (string) $size);
+
+        $chunk = 1024 * 64; // 64KB
+        if ($speed_kb > 0) {
+            $chunk = max(1024, min($chunk, $speed_kb * 1024));
+        }
+
+        $fh = fopen($path, 'rb');
+        if (!$fh) {
+            $this->fail_410();
+        }
+        while (!feof($fh)) {
+            $buf = fread($fh, $chunk);
+            if ($buf === false) {
+                break;
+            }
+            echo $buf;
+            if (function_exists('flush')) {
+                flush();
+            }
+            if ($speed_kb > 0) {
+                // Approximate throttle: sleep 1s per speed_kb window when chunk ~= speed_kb KB.
+                usleep(200000); // 0.2s per chunk for smoother throttle
+            }
+        }
+        fclose($fh);
+    }
+
     private function fail_410(): void {
         status_header(410);
         nocache_headers();