AVideo has SSRF in Scheduler Plugin via callbackURL Missing `isSSRFSafeURL()` Validation

WWBN AVideo is an open source video platform. Prior to version 26.0, the Scheduler plugin's `run()` function in `plugin/Scheduler/Scheduler.php` calls `url_get_contents()` with an admin-configurable `callbackURL` that is validated only by `isValidURL()` (URL format check). Unlike other AVideo endpoints that were recently patched for SSRF (GHSA-9x67-f2v7-63rw, GHSA-h39h-7cvg-q7j6), the Scheduler's callback URL is never passed through `isSSRFSafeURL()`, which blocks requests to RFC-1918 private addresses, loopback, and cloud metadata endpoints. An admin can configure a scheduled task with an internal network `callbackURL` to perform SSRF against cloud infrastructure metadata services or internal APIs not otherwise reachable from the internet. Version 26.0 contains a patch for the issue.