v6.4.2

Fixed

📚 Lesson Preparation — Member access & per-lesson settings now save

• Member selections are saved again. The "الأعضاء المسموح لهم" picker silently dropped every selection. The per-grade access list is sent as a JSON string, but WordPress slash-escapes all $_POST data (magic quotes); the un-unslashed JSON failed to decode (json_decode returned null), so set_lesson_access() was never called. The result: members saw no lessons, and reopening the wizard showed every checkbox unchecked. create_lesson/update_lesson now wp_unslash() the access payload before decoding (the bare grades array was unaffected only because it contains no quote characters).
• Per-lesson quiz, points & AI-detection settings persist. The same magic-quote issue caused quiz_config, prep_points_config, ai_detection_config, and pdf_urls to be stored as invalid (slash-escaped) JSON, so on read they decoded to empty and silently fell back to the global defaults. These are now unslashed before storage.

Note: lessons saved before this fix have no stored member access — reopen each one, reselect members per grade, and save again.