Pixmenia v18 Deep Audit Clean Report

Fixed files:
- includes/ai_services.php
- pixboost_app/includes/ai_services.php
- removed deleted refs from REMOVED_SERVICES.txt

PHP syntax:
PASS: No PHP syntax errors detected.

Removed service references:
PASS: No functional references to deleted services found.

Important live-server checks:
- Run sql/v17_enhancer_only_cleanup.sql on existing database.
- Test Stripe webhook and PayPal webhook in live/test mode.
- Test image enhancement success and failure to confirm credit deduction/refund.
- Confirm upload max size and allowed MIME types on server.