Templately <= 3.4.8 - Unauthenticated Limited Arbitrary JSON File Write

The Templately plugin for WordPress is vulnerable to Arbitrary File Write in all versions up to, and including, 3.4.8. This is due to inadequate input validation in the `save_template_to_file()` function where user-controlled parameters like `session_id`, `content_id`, and `ai_page_ids` are used to construct file paths without proper sanitization. This makes it possible for unauthenticated attackers to write arbitrary `.ai.json` files to locations within the uploads directory.