- The settings form and the AJAX section save both went through
TMDO_Mode_Manager::set() and dropped its WP_Error: an unsafe jump or a
Promotion Guard refusal still said "saved" while the mode stayed put
- TMDO_Admin::apply_bridge_modes() returns the refusals; the full form keeps
them in a per-user transient and shows them after the redirect, the AJAX
save returns them as the error message (the settings JS shows it)
- Verify: AdminBridgeModeSaveTest (5 new); unit 709, integration 606, phpcs 0, stan OK
- PR: PR-135 (manual F-2)