Added aggressive cache clearing after toggle.
Issue:
- update_option saves to DB correctly
- But $method->enabled is loaded when zone object is created
- Zone object is cached, so it keeps old enabled value
- Next request loads cached zone with old enabled="yes"
Solution:
✅ Save instance_settings to DB
✅ Delete shipping method count transient
✅ Clear shipping_zones cache (all zones)
✅ Clear specific zone cache by ID
✅ Update $method->enabled in memory
✅ Clear global shipping cache version
This forces WooCommerce to:
1. Reload zone from database
2. Reload methods from database
3. Read fresh enabled value
4. Display correct state
Test: Toggle should now persist correctly
fa4c4a1402